The Great Race is a race that takes you through downtown Pittsburgh and ends in Point State Park. You run on the Lincoln Parkway for part of the race.
It takes place on the last Sunday of every September and there is a 10K (6.2 miles) and 5K (3.1 mile) race.
I ran the 10K race last year along with about 9,000 other people (the rest were in the 5K). There are so many people that I didn't pass the actual start line until about 5 minutes after the race started.
It's not an issue though as each runner has a chip in his/her bib and this records the time that you individually pass the start line as well as each mile marker along the race. The start of the race is really crowded. I was actually running on the sidewalk at the beginning, where there was a little more room.
There are also lot of people passing out water throughout the race.
The 5K starts in Oakland and the 10K near Frick Park. There are shuttles that travel between the finish line and start line BEFORE the race starts. Otherwise, you need to have someone pick you up from downtown after. The race is limited to 15,000 runners and it does fill up! Be sure to register at least a month before the race. It's $25 before August and $30 after.