PKD is about an hour and a half from DC and less than an hour from Richmond, VA. Here are a couple prices:
1 day admission: $33.99
Season Pass: $69.99
King's Dominion is one park I might recomend over two days at because the lines can be VERY long, and the crowd can get pretty big. Also I've tried with my friends, and we went down on a low-crowd day and spent the whole day there and still missed a couple rides. If you are planning a visit, or for more information, make sure to check out the Official PKD website .

Favorite PKD coasters

Paramout's King's Dominion Overall Review

PKD is my home park and I'm a season pass holder, so I'm pretty loyal to it. The park is not very clean, in fact, it has the worst graffitti problem I've seen at a major park. The employees are good, and the park has a very good lay out of rides and a very good job on the themed areas (Congo, Candy Apple Grove, Wayne's World, and Old Dominion). The lines can get long, the longest wait is for Volcano: The Blast Coaster.

PKD Top Coasters

Oldest: Rebel Yell + Scooby Doo (23 years)
Longest: Rebel Yell (3,685feet)
Fastest: Volcano (up to 70mph)
Largest Capacity: Anaconda (1,400rph)
Tallest Lift Hill: Anaconda (128feet)
Favorite Non-Roller Coaster Ride: Berserker