Fire crews would be able to establish "battle lines" between the blaze and Cowtown.
Fire departments in Denton County fought a massive grass fire started by a piece of farming equipment that caught fire.
The Texas Forest Service says five people have received medical attention following a brush fire that destroyed 15 mobile homes.
White House officials says the disaster declaration paves the way for federal aid to supplement state and local recovery efforts.
State foresters are hoping that recent rains will limit the 2012 wildfire risk in East Texas.
State officials estimate that almost all of Possum Kingdom Lake Park has burned.
Weatherford's fire marshal says seven wildfires in one neighborhood since December were intentionally set.
Willie Nelson, the Dixie Chicks, Lyle Lovett, and Asleep at the Wheel will perform in Austin on Oct. 17.
The fire around Possum Kingdom Lake is now 50 percent contained.
Firefighting crews started Wednesday to gain control of a wind-fueled blaze that has raged unchecked across parched Central Texas for days.