April 4 – The United States Congress adopts the flag of the United States as having thirteen red and white stripes and one star for each state (twenty) with additional stars to be added whenever a new state is added to the Union.
April 7 – Brooks Brothers, the oldest men's clothier in the United States, opens its first store on the northeast corner of Catherine and Cherry Streets in New York City, where the later South Street Seaport stands.
April 14–August 9 – United States Survey of the Coast operations suspended.