> Pittsburgh is spelled with an h, but Gettysburg isn't.
There's some interesting history behind this, which I learned on a tour. The US Board on Geographic Names standardized place names in 1891 by dropping the h from places ending in "burgh". However, residents of Pittsburgh didn't like this change and lobbied for the original spelling, which was restored in 1911. So that's why you have Pittsburg CA and Pittsburgh PA.
There's some interesting history behind this, which I learned on a tour. The US Board on Geographic Names standardized place names in 1891 by dropping the h from places ending in "burgh". However, residents of Pittsburgh didn't like this change and lobbied for the original spelling, which was restored in 1911. So that's why you have Pittsburg CA and Pittsburgh PA.