What kind of a branch is infantry?

The infantry is a branch of the United States Army, and it was first established in 1775. The branch insignia consists of two gold colored muskets that are crossed. The branch plaque has the insignia, but placed on a blue background and with gold letters around. The text says "Infantry United States Army". The infantry was originally men walking on foot, armed with muskets and later rifles. The infantry is the oldest branch of the U.S. Military. Respect.