Monroe is a town in Orange County, New York, United States. The population was 21,387 at the 2020 census, compared to 39,912 at the 2010 census; the significant fall in census population was due to the secession of the town of Palm Tree in 2019. The town is named after President James Monroe.

The first settlers to this land were American Indians from the Leni-Lenape Indian nation. The Leni-Lenape nation consisted of three tribes: the Unulactus, the turkey tribe; Minsis, the wolf tribe; and the Unamis, the turtle tribe. As white settlers started to move north, the Leni-Lenape were forced to move west, out of New York and New Jersey into Pennsylvania and later into central North America, under the treaty of Easton, a colonial agreement signed in October 1758. The British colonial government of the province of Pennsylvania and the Native American tribes in the Ohio country signed this document stating they would be allies in the French and Indian War.

In the early 1700s the lower Hudson Valley region was being mapped out to be divided up under the crown. On March 25, 1707, the "Chessecocks Patent was granted by Queen Anne". The patent confirmed deeds that had been previously acquired by purchase directly from the Leni-Lenape nation. The patent was given to seven people, six men and one woman. Cheesecocks as a precinct included all of present-day Monroe, Palm Tree, Woodbury, Tuxedo, and Stony Point. Many of the patentees never saw the land they bought or were given. Many of the new settlers to come with the Cheesecocks patent were Dutch and English. Both groups of settlers came from Long Island for the rich natural resources.

The original name for the area on the Ramapo River, surveyed by General Washington's geographer and surveyor Robert Erskine, was Smith's Mill, described by Erskine as being "on a sudden bend of the Ramapo." This site still contains the ruins of the grist mill built in 1741 by David Smith, the first settler (Map of Orange and Rockland Counties Area laid down by R. Erskine 1778–1779). The Clove Road, which led from Haverstraw, home of Sir William Smith, up through Tuxedo and the rocky defile known by the Dutch word "kloof", for Clove, was vital to the American cause during the Revolutionary War. It was unknown to the British patrolling the Hudson and gave Washington his escape route from New York to his New Windsor headquarters. Created on March 23, 1799 The town was first named Cheescock's (from the Algonquin words chis, meaning “up,” and kauk, meaning “land,” together signifying “upland”), it was renamed Southfields in 1802, and on April 6, 1808, it took its present name of Monroe (originally spelled Munroe, popularized as Monroe, c1818).

Quoting from Gen George Washington's daily journal:

July 15, [1777]. To Sovereign (Suffern's or Suffren's) Tavern, near the entrance to Smith's Clove. On Sunday, July 20, 1777, Washington has moved on northward into the Ramapo Valley and to the place then known as Galloway's, which is now the village of Southfields (Belcher, p. 81).

David Smith, a prosperous miller of Smithtown, Long Island, bought land from one of the original patentees, Philip Livingston. Smith "purchased lot 43, consisting of 276 acres. He built the first home." Smith built a dam and a grist mill on the Ramapo River, which created the Mill Pond of today, as well as homes for himself and his four sons.

In 1889, a further division of the town resulted in a loss of territory to the towns of Woodbury and Tuxedo. In 1894, the community of Monroe set itself apart from the town by incorporating as a village.