Which is bigger brigade or regiment?

battalion usually has regiments 10x10 WW2 US Infantry Division Organization An Infantry Division was approximatly 15,000 men and included 3 infantry Regiments, 3 artillery Battalions and supporting units. Each Regiment contained 12 Companies that were divided into 3 Battalions. A company was 250 men. The infantry battalion was commanded by a Colonel and was the primary combat unit in the field. It contained 3 rifle companies and 1 heavy weapons company(total of 4). It had a Headquarters command and support units. A Field Artillery Battalion contained 3 Batteries that operated the artillery, 1 service battery and 1 headquarters battery. Each Battery was about 200 men but the service battery was smaller. The Infantry Division also included one Combat Engineer Battalion, that was consisted of 3 companies.