This old postcard features the former U.S. Post Office in Williamsport, Pennsylvania. It was postmarked on June 1, 1906, and mailed from Williamsport to Wigton, in Clearfield County, Pennsylvania. (I can't even find much evidence that "Wigton" exists any more.)
The note on the front states: "Arrived safe Think the City beautiful."
Regarding this building, according to Wikipedia:
"United States Post Office, now known as Williamsport City Hall, is a historic city hall located at Williamsport, Lycoming County, Pennsylvania. It was built between 1888 and 1891, and is a 2½- to 3-story building, with a 2-story addition and 6-story tower. The exterior is faced with rough-faced gray limestone ashlar. It was designed by the Office of the Supervising Architect under the direction of William A. Freret (1833–1911). It was added to the National Register of Historic Places in 1972."
Here's a link to what it looks like these days.
One of the interesting things about the postcard is that it has an added feature of a substance that we might call glitter glue (colored bronze) added to some of the lines of the building and also to the streetcar tracks. It's a bit difficult to see, so here's a closer look...