diff --git a/README.md b/README.md
index 49a6123..61ced1b 100644
--- a/README.md
+++ b/README.md
@@ -67,27 +67,30 @@ import * as journalize from 'journalize';
 - [aptime](#aptime)
   - [Parameters](#parameters-3)
   - [Examples](#examples-3)
-- [capfirst](#capfirst)
+- [apstate](#apstate)
   - [Parameters](#parameters-4)
   - [Examples](#examples-4)
-- [intcomma](#intcomma)
+- [capfirst](#capfirst)
   - [Parameters](#parameters-5)
   - [Examples](#examples-5)
-- [intword](#intword)
+- [intcomma](#intcomma)
   - [Parameters](#parameters-6)
   - [Examples](#examples-6)
-- [ordinal](#ordinal)
+- [intword](#intword)
   - [Parameters](#parameters-7)
   - [Examples](#examples-7)
-- [pluralize](#pluralize)
+- [ordinal](#ordinal)
   - [Parameters](#parameters-8)
   - [Examples](#examples-8)
-- [widont](#widont)
+- [pluralize](#pluralize)
   - [Parameters](#parameters-9)
   - [Examples](#examples-9)
-- [yesno](#yesno)
+- [widont](#widont)
   - [Parameters](#parameters-10)
   - [Examples](#examples-10)
+- [yesno](#yesno)
+  - [Parameters](#parameters-11)
+  - [Examples](#examples-11)
 
 ### apdate
 
@@ -196,6 +199,46 @@ journalize.aptime();
 // returns '6:45 p.m.' (pretend it is actually 6:45 p.m. right now)
 ```
 
+### apstate
+
+Returns a state name, state abbreviation, or AP-formatted state string that corresponds with the supplied input and input/output types.
+
+#### Parameters
+
+- `val` **[string](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)**
+- `from` **[string](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)**
+- `to` **[string](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)**
+
+#### Examples
+
+```javascript
+var journalize = require('journalize');
+
+// State name to AP style
+journalize.apstate('New York', 'state', 'ap');
+// returns 'N.Y.'
+
+//State name to state abbreviation
+journalize.apstate('Wisconsin', 'state', 'abbrev');
+// returns 'WI'
+
+//State abbreviation to AP style
+journalize.apstate('CA', 'abbrev', 'ap');
+// returns 'Calif.'
+
+//State abbreviation to state name
+journalize.apstate('SD', 'abbrev', 'state'); 
+// returns 'South Dakota'
+
+//AP style to state abbreviation
+journalize.apstate('Ariz.', 'ap', 'abbrev');
+// returns 'AZ'
+
+//AP style to state name
+journalize.apstate('N.H.', 'ap', 'state');
+// returns 'New Hampshire'
+```
+
 Returns **[string](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)**
 
 ### capfirst
diff --git a/__tests__/apstate.test.js b/__tests__/apstate.test.js
new file mode 100644
index 0000000..22acac8
--- /dev/null
+++ b/__tests__/apstate.test.js
@@ -0,0 +1,48 @@
+import apstate from '../src/apstate';
+
+describe('apstate', () => {
+  it('should convert state to ap style', () => {
+    expect(apstate('New York', 'state', 'ap')).toBe('N.Y.');
+  });
+
+  it('should convert state to abbrev', () => {
+    expect(apstate('Wisconsin', 'state', 'abbrev')).toBe('WI');
+  });
+
+  it('should convert abbrev to ap style`', () => {
+    expect(apstate('CA', 'abbrev', 'ap')).toBe('Calif.');
+  });
+
+  it('should convert abbrev to state`', () => {
+    expect(apstate('SD', 'abbrev', 'state')).toBe('South Dakota');
+  });
+
+  it('should convert ap style to abbrev', () => {
+    expect(apstate('Ariz.', 'ap', 'abbrev')).toBe('AZ');
+  });
+
+  it('should convert ap style to state', () => {
+    expect(apstate('N.H.', 'ap', 'state')).toBe('New Hampshire');
+  });
+
+  it('should throw error for invalid argument', () => {
+    expect(() => {
+      apstate('N.H.', 'blah', 'state');
+    }).toThrow(Error);
+    expect(() => {
+      apstate('N.H.', 'state', 'blah');
+    }).toThrow(Error);
+  });
+
+  it('should throw error for invalid state or mismatched state', () => {
+    expect(() => {
+      apstate('i am not a state', 'blah', 'state');
+    }).toThrow(Error);
+    expect(() => {
+      apstate('N.H.', 'state', 'state');
+    }).toThrow(Error);
+    expect(() => {
+      apstate('New Hampshire', 'abbrev', 'state');
+    }).toThrow(Error);
+  });
+});
diff --git a/src/apstate.js b/src/apstate.js
new file mode 100644
index 0000000..ed494a1
--- /dev/null
+++ b/src/apstate.js
@@ -0,0 +1,689 @@
+import { isNil } from './utils';
+
+/**
+ * List of possible formats
+ * @private
+ * @type {Array}
+ */
+const TYPES = ['state', 'abbrev', 'ap'];
+
+/**
+ * List of state mappings
+ * @private
+ * @type {Array}
+ */
+const MAPPINGS = {
+  state: {
+    Alabama: {
+      abbrev: 'AL',
+      ap: 'Ala.',
+    },
+    Alaska: {
+      abbrev: 'AK',
+      ap: 'Alaska',
+    },
+    Arizona: {
+      abbrev: 'AZ',
+      ap: 'Ariz.',
+    },
+    Arkansas: {
+      abbrev: 'AR',
+      ap: 'Ark.',
+    },
+    California: {
+      abbrev: 'CA',
+      ap: 'Calif.',
+    },
+    Colorado: {
+      abbrev: 'CO',
+      ap: 'Colo.',
+    },
+    Connecticut: {
+      abbrev: 'CT',
+      ap: 'Conn.',
+    },
+    Delaware: {
+      abbrev: 'DE',
+      ap: 'Del.',
+    },
+    'District of Columbia': {
+      abbrev: 'DC',
+      ap: 'D.C.',
+    },
+    Florida: {
+      abbrev: 'FL',
+      ap: 'Fla.',
+    },
+    Georgia: {
+      abbrev: 'GA',
+      ap: 'Ga.',
+    },
+    Hawaii: {
+      abbrev: 'HI',
+      ap: 'Hawaii',
+    },
+    Idaho: {
+      abbrev: 'ID',
+      ap: 'Idaho',
+    },
+    Illinois: {
+      abbrev: 'IL',
+      ap: 'Ill.',
+    },
+    Indiana: {
+      abbrev: 'IN',
+      ap: 'Ind.',
+    },
+    Iowa: {
+      abbrev: 'IA',
+      ap: 'Iowa',
+    },
+    Kansas: {
+      abbrev: 'KS',
+      ap: 'Kan.',
+    },
+    Kentucky: {
+      abbrev: 'KY',
+      ap: 'Ky.',
+    },
+    Louisiana: {
+      abbrev: 'LA',
+      ap: 'La.',
+    },
+    Maine: {
+      abbrev: 'ME',
+      ap: 'Maine',
+    },
+    Maryland: {
+      abbrev: 'MD',
+      ap: 'Md.',
+    },
+    Massachusetts: {
+      abbrev: 'MA',
+      ap: 'Mass.',
+    },
+    Michigan: {
+      abbrev: 'MI',
+      ap: 'Mich.',
+    },
+    Minnesota: {
+      abbrev: 'MN',
+      ap: 'Minn.',
+    },
+    Mississippi: {
+      abbrev: 'MS',
+      ap: 'Miss.',
+    },
+    Missouri: {
+      abbrev: 'MO',
+      ap: 'Mo.',
+    },
+    Montana: {
+      abbrev: 'MT',
+      ap: 'Mont.',
+    },
+    Nebraska: {
+      abbrev: 'NE',
+      ap: 'Neb.',
+    },
+    Nevada: {
+      abbrev: 'NV',
+      ap: 'Nev.',
+    },
+    'New Hampshire': {
+      abbrev: 'NH',
+      ap: 'N.H.',
+    },
+    'New Jersey': {
+      abbrev: 'NJ',
+      ap: 'N.J.',
+    },
+    'New Mexico': {
+      abbrev: 'NM',
+      ap: 'N.M.',
+    },
+    'New York': {
+      abbrev: 'NY',
+      ap: 'N.Y.',
+    },
+    'North Carolina': {
+      abbrev: 'NC',
+      ap: 'N.C.',
+    },
+    'North Dakota': {
+      abbrev: 'ND',
+      ap: 'N.D.',
+    },
+    Ohio: {
+      abbrev: 'OH',
+      ap: 'Ohio',
+    },
+    Oklahoma: {
+      abbrev: 'OK',
+      ap: 'Okla.',
+    },
+    Oregon: {
+      abbrev: 'OR',
+      ap: 'Ore.',
+    },
+    Pennsylvania: {
+      abbrev: 'PA',
+      ap: 'Pa.',
+    },
+    'Rhode Island': {
+      abbrev: 'RI',
+      ap: 'R.I.',
+    },
+    'South Carolina': {
+      abbrev: 'SC',
+      ap: 'S.C.',
+    },
+    'South Dakota': {
+      abbrev: 'SD',
+      ap: 'S.D.',
+    },
+    Tennessee: {
+      abbrev: 'TN',
+      ap: 'Tenn.',
+    },
+    Texas: {
+      abbrev: 'TX',
+      ap: 'Texas',
+    },
+    Utah: {
+      abbrev: 'UT',
+      ap: 'Utah',
+    },
+    Vermont: {
+      abbrev: 'VT',
+      ap: 'Vt.',
+    },
+    Virginia: {
+      abbrev: 'VA',
+      ap: 'Va.',
+    },
+    Washington: {
+      abbrev: 'WA',
+      ap: 'Wash.',
+    },
+    'West Virginia': {
+      abbrev: 'WV',
+      ap: 'W.Va.',
+    },
+    Wisconsin: {
+      abbrev: 'WI',
+      ap: 'Wis.',
+    },
+    Wyoming: {
+      abbrev: 'WY',
+      ap: 'Wyo.',
+    },
+  },
+  abbrev: {
+    AL: {
+      state: 'Alabama',
+      ap: 'Ala.',
+    },
+    AK: {
+      state: 'Alaska',
+      ap: 'Alaska',
+    },
+    AZ: {
+      state: 'Arizona',
+      ap: 'Ariz.',
+    },
+    AR: {
+      state: 'Arkansas',
+      ap: 'Ark.',
+    },
+    CA: {
+      state: 'California',
+      ap: 'Calif.',
+    },
+    CO: {
+      state: 'Colorado',
+      ap: 'Colo.',
+    },
+    CT: {
+      state: 'Connecticut',
+      ap: 'Conn.',
+    },
+    DE: {
+      state: 'Delaware',
+      ap: 'Del.',
+    },
+    DC: {
+      state: 'District of Columbia',
+      ap: 'D.C.',
+    },
+    FL: {
+      state: 'Florida',
+      ap: 'Fla.',
+    },
+    GA: {
+      state: 'Georgia',
+      ap: 'Ga.',
+    },
+    HI: {
+      state: 'Hawaii',
+      ap: 'Hawaii',
+    },
+    ID: {
+      state: 'Idaho',
+      ap: 'Idaho',
+    },
+    IL: {
+      state: 'Illinois',
+      ap: 'Ill.',
+    },
+    IN: {
+      state: 'Indiana',
+      ap: 'Ind.',
+    },
+    IA: {
+      state: 'Iowa',
+      ap: 'Iowa',
+    },
+    KS: {
+      state: 'Kansas',
+      ap: 'Kan.',
+    },
+    KY: {
+      state: 'Kentucky',
+      ap: 'Ky.',
+    },
+    LA: {
+      state: 'Louisiana',
+      ap: 'La.',
+    },
+    ME: {
+      state: 'Maine',
+      ap: 'Maine',
+    },
+    MD: {
+      state: 'Maryland',
+      ap: 'Md.',
+    },
+    MA: {
+      state: 'Massachusetts',
+      ap: 'Mass.',
+    },
+    MI: {
+      state: 'Michigan',
+      ap: 'Mich.',
+    },
+    MN: {
+      state: 'Minnesota',
+      ap: 'Minn.',
+    },
+    MS: {
+      state: 'Mississippi',
+      ap: 'Miss.',
+    },
+    MO: {
+      state: 'Missouri',
+      ap: 'Mo.',
+    },
+    MT: {
+      state: 'Montana',
+      ap: 'Mont.',
+    },
+    NB: {
+      state: 'Nebraska',
+      ap: 'Neb.',
+    },
+    NV: {
+      state: 'Nevada',
+      ap: 'Nev.',
+    },
+    NH: {
+      state: 'New Hampshire',
+      ap: 'N.H.',
+    },
+    NJ: {
+      state: 'New Jersey',
+      ap: 'N.J.',
+    },
+    NM: {
+      state: 'New Mexico',
+      ap: 'N.M.',
+    },
+    NY: {
+      state: 'New York',
+      ap: 'N.Y.',
+    },
+    NC: {
+      state: 'North Carolina',
+      ap: 'N.C.',
+    },
+    ND: {
+      state: 'North Dakota',
+      ap: 'N.D.',
+    },
+    OH: {
+      state: 'Ohio',
+      ap: 'Ohio',
+    },
+    OK: {
+      state: 'Oklahoma',
+      ap: 'Okla.',
+    },
+    OR: {
+      state: 'Oregon',
+      ap: 'Ore.',
+    },
+    PA: {
+      state: 'Pennsylvania',
+      ap: 'Pa.',
+    },
+    RI: {
+      state: 'Rhode Island',
+      ap: 'R.I.',
+    },
+    SC: {
+      state: 'South Carolina',
+      ap: 'S.C.',
+    },
+    SD: {
+      state: 'South Dakota',
+      ap: 'S.D.',
+    },
+    TN: {
+      state: 'Tennessee',
+      ap: 'Tenn.',
+    },
+    TX: {
+      state: 'Texas',
+      ap: 'Texas',
+    },
+    UT: {
+      state: 'Utah',
+      ap: 'Utah',
+    },
+    VT: {
+      state: 'Vermont',
+      ap: 'Vt.',
+    },
+    VA: {
+      state: 'Virginia',
+      ap: 'Va.',
+    },
+    WA: {
+      state: 'Washington',
+      ap: 'Wash.',
+    },
+    WV: {
+      state: 'West Virginia',
+      ap: 'W.Va.',
+    },
+    WI: {
+      state: 'Wisconsin',
+      ap: 'Wis.',
+    },
+    WY: {
+      state: 'Wyoming',
+      ap: 'Wyo.',
+    },
+  },
+  ap: {
+    'Ala.': {
+      state: 'Alabama',
+      abbrev: 'AL',
+    },
+    Alaska: {
+      state: 'Alaska',
+      abbrev: 'AK',
+    },
+    'Ariz.': {
+      state: 'Arizona',
+      abbrev: 'AZ',
+    },
+    'Ark.': {
+      state: 'Arkansas',
+      abbrev: 'AR',
+    },
+    'Calif.': {
+      state: 'California',
+      abbrev: 'CA',
+    },
+    'Colo.': {
+      state: 'Colorado',
+      abbrev: 'CO',
+    },
+    'Conn.': {
+      state: 'Connecticut',
+      abbrev: 'CT',
+    },
+    'Del.': {
+      state: 'Delaware',
+      abbrev: 'DE',
+    },
+    'D.C.': {
+      state: 'District of Columbia',
+      abbrev: 'DC',
+    },
+    'Fla.': {
+      state: 'Florida',
+      abbrev: 'FL',
+    },
+    'Ga.': {
+      state: 'Georgia',
+      abbrev: 'GA',
+    },
+    Hawaii: {
+      state: 'Hawaii',
+      abbrev: 'HI',
+    },
+    Idaho: {
+      state: 'Idaho',
+      abbrev: 'ID',
+    },
+    'Ill.': {
+      state: 'Illinois',
+      abbrev: 'IL',
+    },
+    'Ind.': {
+      state: 'Indiana',
+      abbrev: 'IN',
+    },
+    Iowa: {
+      state: 'Iowa',
+      abbrev: 'IA',
+    },
+    'Kan.': {
+      state: 'Kansas',
+      abbrev: 'KS',
+    },
+    'Ky.': {
+      state: 'Kentucky',
+      abbrev: 'KY',
+    },
+    'La.': {
+      state: 'Louisiana',
+      abbrev: 'LA',
+    },
+    Maine: {
+      state: 'Maine',
+      abbrev: 'ME',
+    },
+    'Md.': {
+      state: 'Maryland',
+      abbrev: 'MD',
+    },
+    'Mass.': {
+      state: 'Massachusetts',
+      abbrev: 'MA',
+    },
+    'Mich.': {
+      state: 'Michigan',
+      abbrev: 'MI',
+    },
+    'Minn.': {
+      state: 'Minnesota',
+      abbrev: 'MN',
+    },
+    'Miss.': {
+      state: 'Mississippi',
+      abbrev: 'MS',
+    },
+    'Mo.': {
+      state: 'Missouri',
+      abbrev: 'MO',
+    },
+    'Mont.': {
+      state: 'Montana',
+      abbrev: 'MT',
+    },
+    'Neb.': {
+      state: 'Nebraska',
+      abbrev: 'NE',
+    },
+    'Nev.': {
+      state: 'Nevada',
+      abbrev: 'NV',
+    },
+    'N.H.': {
+      state: 'New Hampshire',
+      abbrev: 'NH',
+    },
+    'N.J.': {
+      state: 'New Jersey',
+      abbrev: 'NJ',
+    },
+    'N.M.': {
+      state: 'New Mexico',
+      abbrev: 'NM',
+    },
+    'N.Y.': {
+      state: 'New York',
+      abbrev: 'NY',
+    },
+    'N.C.': {
+      state: 'North Carolina',
+      abbrev: 'NC',
+    },
+    'N.D.': {
+      state: 'North Dakota',
+      abbrev: 'ND',
+    },
+    Ohio: {
+      state: 'Ohio',
+      abbrev: 'Ohio',
+    },
+    'Okla.': {
+      state: 'Oklahoma',
+      abbrev: 'OK',
+    },
+    'Ore.': {
+      state: 'Oregon',
+      abbrev: 'OR',
+    },
+    'Pa.': {
+      state: 'Pennsylvania',
+      abbrev: 'PA',
+    },
+    'R.I.': {
+      state: 'Rhode Island',
+      abbrev: 'RI',
+    },
+    'S.C.': {
+      state: 'South Carolina',
+      abbrev: 'SC',
+    },
+    'S.D.': {
+      state: 'South Dakota',
+      abbrev: 'SD',
+    },
+    'Tenn.': {
+      state: 'Tennessee',
+      abbrev: 'TN',
+    },
+    Texas: {
+      state: 'Texas',
+      abbrev: 'TX',
+    },
+    Utah: {
+      state: 'Utah',
+      abbrev: 'UT',
+    },
+    'Vt.': {
+      state: 'Vermont',
+      abbrev: 'VT',
+    },
+    'Va.': {
+      state: 'Virginia',
+      abbrev: 'VA',
+    },
+    'Wash.': {
+      state: 'Washington',
+      abbrev: 'WA',
+    },
+    'W.Va.': {
+      state: 'West Virginia',
+      abbrev: 'WV',
+    },
+    'Wis.': {
+      state: 'Wisconsin',
+      abbrev: 'WI',
+    },
+    'Wyo.': {
+      state: 'Wyoming',
+      abbrev: 'WY',
+    },
+  },
+};
+
+/**
+ * Converts a state name to its abbreviation or AP style, and vice versa. If a
+ * state could not be converted, it is returned in its original form.
+ *
+ * If a non-integer is given, it will be returned in its original form as
+ * well.
+ *
+ * @param  {string} val
+ * @param {string} from
+ * @param {string} to
+ * @return {string}
+ * @example
+ *
+ * var journalize = require('journalize');
+ *
+ * journalize.apstate('New York', 'state', 'ap');
+ * // returns 'N.Y.'
+ *
+ * journalize.apstate('Wisconsin', 'state', 'abbrev');
+ * // returns 'WI'
+ *
+ * journalize.apstate('CA', 'abbrev', 'ap');
+ * // returns 'Calif.'
+ *
+ * journalize.apstate('SD', 'abbrev', 'state');
+ * // returns 'South Dakota'
+ *
+ * journalize.apstate('Ariz.', 'ap', 'abbrev');
+ * // returns 'AZ'
+ *
+ * journalize.apstate('N.H.', 'ap', 'state');
+ * // returns 'New Hampshire
+ */
+export default function apstate(val, from, to) {
+  // if `val` is undefined or null, return an empty string
+  if (isNil(val) || isNil(from) || isNil(to)) return '';
+
+  //if `from` is not a valid type`
+  if (!TYPES.includes(from)) {
+    throw new Error("the <to> parameter must be 'state', 'abbrev', or 'ap'");
+  }
+
+  //if `to` is not a valid type`
+  if (!TYPES.includes(to)) {
+    throw new Error("the <from> parameter must be 'state', 'abbrev', or 'ap'");
+  }
+
+  //if `from` and `val` are mismatched, i.e. N.H. is not a state, it is an abbrev
+  if (isNil(MAPPINGS[from][val])) {
+    throw new Error(`${val} is not a valid ${from}`);
+  }
+
+  return MAPPINGS[from][val][to];
+}