The Charles Street 12 Miler (or "Chuck 12") is a large event put on by Charm City Run and is majorly sponsored by Under Armour. It is the third event in the B3 Challenge, which also includes the Shamrock 5K in March and the Sole of the City 10K in April.
This course can be a bit challenging but it is a fun course and goes from Baltimore County to Under Armour in Baltimore City. There are some neat landmarks along the way. The weather is usually hot and humid, but other than that, a great race. Usually they have good food at the end.