What is first division?

Answer 1

It is a combat formation of the US Army. Before World War One, except during wars, the US Army was mostly scattered in small detachments in frontier forts and coastal installations. It was rare to see so much as a regiment assembled in one place.

When the US entered WWI, it had to create a large army for fighting in Europe, so once more divisions were created. The modern organization of the US army goes back to this time, 1917.

WWI US divisions were very large, with over 26,000 men. All of them were infantry divisions, meaning they were intended for ground combat, and made up of foot soldiers. Each division had four regiments, in two brigades (two regiments to a brigade). In the 1st Infantry Division, the four regiments were the 16th, 18th, 26th and 28th Regiments of Infantry. The army called these "square" divisions.

Just before WWII the US redesigned its infantry divisions. The new design was the "triangular" division, with three infantry regiments, instead of four. Brigades were done away with. Regiments were smaller, so the new triangular divisions had just under 15,000 men. In the WWII "triangular" 1st US Infantry Division, the three infantry regiments were the 16th, 18th and 26th Regiments of Infantry.

The US 1st Infantry Division was the first one organized in 1917, making it the oldest division in the US Army. It has been in continuous service since 1917. Its members wear a patch on the shoulder of their uniforms, which is a shield with a large, red numeral "1" on it, giving the Division the nickname "Big Red One". The Division was one of three US infantry divisions which hit the beach in the D-Day landings in France on June 6, 1944.