Yep, the hamburger as we know it was invented right here in Western New York. Back in 1885 there were two guys who would always come up to the Erie County Fair (back in 1885 it was called the HAMBURG FAIR) and sell food.

They would sell pulled pork, but one day they ran out and instead used ground beef with coffee, brown sugar + other ingredients. People loved them and since they were at the Hamburg Fair, they called them "HAMBURGERS".

Today is National Hamburger Day
September 18

According to the Erie County Fair site:

Until the early 1920s, the Erie County Fair was held mid to late September or as late as early October to celebrate the agricultural harvest. The 1885 Erie County Fair, the event that saw the invention of the hamburger, was held September 16th-18th, 1885.