The original land patent for the town was dated 1724, but little was done for decades to develop and settle the region.

Wallkill is bordered by the towns of Hamptonburgh and Montgomery on the east, Crawford on the north, Mamakating and Mount Hope on the west, and Wawayanda and Goshen on the south.

The ethnic makeup of the population was 57.8% white (non-Hispanic), 22.5% Hispanic, 16.0% African-American, 3.2% Asian, and 0.5% Native American.

It is home to many retail stores, shopping centers and restaurants, many of which are located along Route 211, in a suburban pattern related to highway development.

Town taxpayers own an 18-hole golf club which was designed by landscape architect Steve Esposito.

From 2001 to 2006 the department was subject to oversight by a federal court-appointed monitor, the result of a consent decree in a suit brought against the town through the New York Attorney General's office.

The suit was prompted by multiple complaints of harassment of young women and other abuses of police authority.

[5] Wallkill is divided into seven fire districts: Circleville, Howells, Mechanicstown, Silver Lake, Pocatello, Washington Heights, and Bloomingburg.