I am guessing that you are looking at your assessment for real estate tax purposes. In most areas, assessed value is not the same as fair market value. Assessed value is usually less than fair market value.
As Hope indicated, when you bought the property for $102K, that dropped its value It is likely that price became the new "assessed value."
Real estate prices are going up in places other than D.C. Jobs are related. Real estate prices go up in places where home buyers/owners make enough money to buy & keep a home. In this economy, the location with decent living wage jobs makes a difference in real estate prices and the local real estate market.
You may want to look at Emerging Trends in Real Estate 2012 published by the Urban Land Institute. You can view it online.
This report considers all types of real estate, not just residential.
P. 36-37 specifically discusses Dallas/Ft. Worth.
Good luck to the OP