Although The Pike as far as a Pole Arm weapon, went back many of hundreds of years prior to the 19th Century, it made a "resurgence" of such, during The American Civil War of 1861. The Pike was a hand-held weapon designed to inflict both blunt force trauma as well as stabbing injuries. In 19th Century America, the weapon did not catch on as a traditional Infantry weapon, used most as a "Guard Arm". Many 18th Century Police in America used a Pike.
With the advent of The War Between The States, many Confederate Militias initially had no weapons. Most of the early firearms acquisitions came from "captured" Federal Armories. In many cases, these Facilities stored antiquated weapons, including The Pike. Several Southern Regiments were actually fielded with The Pike as their primary weapon. Although quickly replaced with firearms, Pickett (Skirmishers), were detailed to carry them. By the end of 1861, most were gone from use.
Although the Union Army fared better with an abundance of firearms, it was common practice to issue Pikes to the fledgling African-American Troops, that started being deployed in late 1862. However, even they were replaced by traditional rifles by 1863. Naval Forces on both sides still retained Boarding Pikes, although they were rarely used. The typical Infantry Pike was either a wooden or iron shaft, 8-feet long. Unlike it's European "Cousin", no fancy "Head" weapon was added. Often, a simple double edged iron or steel blade, ranging 6 to 8-inches long, topped the Pole. Some featured a side "Hook", again much like a Naval Pike.