diff --git a/public/js/script.js b/public/js/script.js
index bd8eded..74dd19b 100644
--- a/public/js/script.js
+++ b/public/js/script.js
@@ -17,11 +17,13 @@ const operations = [
   { value: "isBoolean", label: "Is Boolean" },
   { value: "isCountry", label: "Is Country" },
   { value: "isValidStateCode", label: "Is Valid State Code" },
+  { value: "isLatLong", label: "Is Latitude/Longitude" },
 ];
 
 async function getResponse() {
   const inputString = document.querySelector("#inputString")?.value;
   const endpoint = document.querySelector("#selectedOperation")?.value;
+  const checkDMS = document.querySelector("#checkDMS")?.checked;
 
   if (!endpoint) {
     alert("Please select an operation first");
@@ -31,12 +33,16 @@ async function getResponse() {
   // Use window.location.origin to get the base URL
   const baseUrl = window.location.origin;
 
+  let requestBody = { inputString };
+
+  if (endpoint === "isLatLong") {
+    requestBody.checkDMS = checkDMS;
+  }
+
   try {
     const response = await fetch(`${baseUrl}/api/${endpoint}`, {
       method: "POST",
-      body: JSON.stringify({
-        inputString: inputString,
-      }),
+      body: JSON.stringify(requestBody),
       headers: {
         "Content-Type": "application/json",
       },
@@ -119,6 +125,8 @@ function clearSelection() {
   const selectedOperation = document.querySelector("#selectedOperation");
   const clearIcon = document.querySelector("#clearSearch");
   const dropdownIcon = document.querySelector("#dropdownToggle");
+  const checkDMSContainer = document.querySelector("#checkDMSContainer");
+  const checkDMS = document.querySelector("#checkDMS");
 
   searchInput.value = "";
   renderOperations(operations);
@@ -126,6 +134,8 @@ function clearSelection() {
   searchResults.style.display = "block";
   clearIcon.style.display = "none";
   dropdownIcon.textContent = "▲";
+  checkDMSContainer.style.display = "none";
+  checkDMS.checked = false;
 }
 
 function selectOperation(operation) {
@@ -140,6 +150,13 @@ function selectOperation(operation) {
   searchResults.style.display = "none";
   clearIcon.style.display = "block";
   dropdownIcon.textContent = "▼";
+
+  if (operation.value === "isLatLong") {
+    checkDMSContainer.style.display = "block";
+  } else {
+    checkDMSContainer.style.display = "none";
+    document.querySelector("#checkDMS").checked = false;
+  }
 }
 
 document.addEventListener("click", (e) => {
diff --git a/server.js b/server.js
index 627a3a6..137dd90 100644
--- a/server.js
+++ b/server.js
@@ -184,6 +184,12 @@ app.use((err, req, res, next) => {
  * @property {boolean} [caseSensitive=true] - Whether the comparison should be case-sensitive (default: true)
  */
 
+/**
+ * A LatLongRequest
+ * @typedef {object} LatLongRequest
+ * @property {string} inputString.required - The latitude and longitude to validate (supports decimal degrees or DMS format)
+ * @property {boolean} [checkDMS=false] - Optionally check if the input is in DMS (Degrees, Minutes, Seconds) format
+ */
 
 /**
  * POST /api/isField
@@ -1086,4 +1092,44 @@ app.post('/api/isValidStateCode', (req, res) => {
   res.json({ result });
 });
 
-module.exports = app;
+/**
+ * POST /api/isLatLong
+ * @summary Returns true if valid latitude and longitude, otherwise false
+ * @description
+ * Supports two formats:
+ * 1. Decimal degrees: e.g. "37.7749,-122.4194" or "37.7749, -122.4194"
+ * 2. DMS (degrees, minutes, seconds): e.g. "37°46'30\"N 122°25'10\"W" (if checkDMS: true)
+ * @param {LatLongRequest} request.body.required - The input string and optional checkDMS flag
+ * @return {BasicResponse} 200 - Success response
+ * @return {BadRequestResponse} 400 - Bad request response
+ * @example request - decimal degrees
+ * {
+ *   "inputString": "34.052235,-118.243683"
+ * }
+ * @example request - DMS
+ * {
+ *   "inputString": "34°3'8.1\"N 118°14'37.2\"W",
+ *   "checkDMS": true
+ * }
+ * @example response - 200 - example payload
+ * {
+ *   "result": true
+ * }
+ * @example response - 400 - example
+ * {
+ *   "error": "Input string required as a parameter."
+ * }
+ */
+app.post('/api/isLatLong', (req, res) => {
+  const { inputString, checkDMS = false } = req.body;
+
+  if (!inputString) {
+    return res.status(400).json({ error: requiredParameterResponse });
+  }
+
+  const result = ValidationFunctions.isLatLong(inputString, { checkDMS });
+
+  res.json({ result });
+});
+
+module.exports = app;
\ No newline at end of file
diff --git a/test/integration/isLatLong.test.js b/test/integration/isLatLong.test.js
new file mode 100644
index 0000000..87ce254
--- /dev/null
+++ b/test/integration/isLatLong.test.js
@@ -0,0 +1,59 @@
+const request = require('supertest');
+const app = require('../../server.js');
+
+describe('POST /api/isLatLong', () => {
+  it('should return true for a valid latitude and longitude in decimal degrees format', async () => {
+    const response = await request(app)
+      .post('/api/isLatLong')
+      .send({ inputString: '34.052235,-118.243683' })
+      .expect(200);
+
+    expect(response.body).toHaveProperty('result', true);
+  });
+
+  it('should return true for a valid latitude and longitude in degrees, minutes, seconds format', async () => {
+    const response = await request(app)
+      .post('/api/isLatLong')
+      .send({ inputString: "34°3'8.1\"N 118°14'37.2\"W", checkDMS: true })
+      .expect(200);
+
+    expect(response.body).toHaveProperty('result', true);
+  });
+
+  it('should return false for an invalid latitude and longitude in decimal degrees format', async () => {
+    const response = await request(app)
+      .post('/api/isLatLong')
+      .send({ inputString: '34.052235,-118.243683,extra' })
+      .expect(200);
+
+    expect(response.body).toHaveProperty('result', false);
+  });
+
+  it('should return false for an invalid latitude and longitude in degrees, minutes, seconds format', async () => {
+    const response = await request(app)
+      .post('/api/isLatLong')
+      .send({ inputString: "34°3'8.1'N 118°14'37.2'W extra", checkDMS: true })
+      .expect(200);
+
+    expect(response.body).toHaveProperty('result', false);
+  });
+
+  it('should return false if inputString is not a string', async () => {
+    const response = await request(app)
+      .post('/api/isLatLong')
+      .send({ inputString: 12345 })
+      .expect(200);
+
+    expect(response.body).toHaveProperty('result', false);
+  });
+
+  it('should return 400 if inputString is missing', async () => {
+    const response = await request(app)
+      .post('/api/isLatLong')
+      .send({})
+      .expect(400);
+
+    expect(response.body).toHaveProperty('error');
+    expect(response.body.error).toBeDefined();
+  });
+});
diff --git a/test/unit/isLatLong.test.js b/test/unit/isLatLong.test.js
new file mode 100644
index 0000000..474667d
--- /dev/null
+++ b/test/unit/isLatLong.test.js
@@ -0,0 +1,31 @@
+const { isLatLong } = require("../../validationFunctions");
+
+describe("isLatLong", () => {
+  it("should return true for valid latitude and longitude in decimal degrees format", () => {
+    expect(isLatLong("34.052235,-118.243683")).toBe(true);
+  });
+
+  it("should return true for valid latitude and longitude in degrees, minutes, seconds format", () => {
+    expect(isLatLong("34°3'8.1\"N 118°14'37.2\"W", { checkDMS: true })).toBe(
+      true
+    );
+  });
+
+  it("should return false for invalid latitude and longitude in decimal degrees format", () => {
+    expect(isLatLong("34.052235,-118.243683,extra")).toBe(false);
+  });
+
+  it("should return false for invalid latitude and longitude in degrees, minutes, seconds format", () => {
+    expect(
+      isLatLong("34°3'8.1'N 118°14'37.2'W extra", { checkDMS: true })
+    ).toBe(false);
+  });
+
+  it("should return false if inputString is not a string", () => {
+    expect(isLatLong(12345)).toBe(false);
+  });
+
+  it("should return false if inputString is an empty string", () => {
+    expect(isLatLong("")).toBe(false);
+  });
+});
diff --git a/validationFunctions.js b/validationFunctions.js
index 2e1f577..94157ad 100644
--- a/validationFunctions.js
+++ b/validationFunctions.js
@@ -450,6 +450,32 @@ module.exports = class ValidationFunctions {
 
     return validStateCodes.includes(inputString);
   }
+
+  /**
+   * Checks if the given string is a valid latitude-longitude coordinate.
+   * 
+   * * Supports two formats:
+   * 1. Decimal degrees: e.g. "37.7749,-122.4194" or "37.7749, -122.4194"
+   * 2. DMS (degrees, minutes, seconds): e.g. "37°46'30\"N 122°25'10\"W" (if checkDMS: true)
+   * 
+   * @param {string} inputString - The coordinate to validate.
+   * @param {Object} [options={ checkDMS: false }] - Options for validation.
+   * @param {boolean} [options.checkDMS=false] - If true, checks for DMS format.
+   * @returns {boolean} - Returns `true` if `inputString` is a valid latitude-longitude coordinate, otherwise `false`.
+   */
+  static isLatLong(inputString, options = { checkDMS: false }) {
+    if (!inputString || typeof inputString !== "string") return false;
+
+    const trimmedInput = inputString.trim();
+
+    if (options.checkDMS) {
+      const dmsRegex = /^(\d{1,3})°\d{1,2}'\d{1,2}(\.\d+)?"[NS]\s+(\d{1,3})°\d{1,2}'\d{1,2}(\.\d+)?"[EW]$/;
+      return dmsRegex.test(trimmedInput);
+    }
+
+    const decimalDegreesRegex = /^-?\d{1,3}(?:\.\d+)?,\s*-?\d{1,3}(?:\.\d+)?$/;
+    return decimalDegreesRegex.test(trimmedInput);
+  }
 }
 
 const handleAxiosError = (error) => {
diff --git a/views/pages/index.pug b/views/pages/index.pug
index 064e9f3..4b9a346 100644
--- a/views/pages/index.pug
+++ b/views/pages/index.pug
@@ -17,6 +17,10 @@ block content
         span(class="dropdown-icon" id="dropdownToggle" onclick="toggleDropdown()") ▼
     div(id="searchResults" class="search-results")
     input(type="hidden" id="selectedOperation")
+    div#checkDMSContainer(style='display: none; margin-top: 8px;')
+        label(for='checkDMS' style='display: flex; align-items: center; gap: 8px;')
+            input#checkDMS(type='checkbox' style='margin: 0;')
+            | Check DMS format (e.g. 34°3'8.1"N 118°14'37.2"W)
     br
     br
     button(onclick='getResponse()' id='getResponseButton' disabled='true') Get Response