Manassas is a board wargame originally published by Historical Concepts in 1974, and republished by Game Designers Workshop (GDW) in 1977 that simulates the First Battle of Bull Run during the American Civil War.

In the first major battle of the American Civil War, poorly trained Union forces under Brigadier General Irvin McDowell marched south from Washington, attempting to attack the Confederate capital of Richmond.

[2] The game box contains: Unlike many wargames that use a "I go, You go" alternating turn system, Manassas uses simultaneous movement.

"[5] In his 1977 book The Comprehensive Guide to Board Wargaming, Nicholas Palmer noted that the first edition of this game had been praised despite being an amateur production.

He called the system of using a marker to denote unit strength "slightly odd", and warned that due to its complexity, this was "Not for beginners.