If you are looking for contact and address information for the actual park, here it is:

2800 Pimville Road
Park Hills, MO 63601

(573) 431-1069

Hours of Operation
Campground 1 is open year-round and can be accessed daily between 7 a.m. and 10 p.m.
Registered campers can request after-hours access by contacting the park office at 573-431-1069 one day prior to their arrival.

Winter Hours (Off-Season)
From October through March, the park grounds are open daily from 7 a.m. to 5 p.m. Gates to day-use areas, which would include the off-road vehicle (ORV) riding area, lakes and Pim day-use area, close at 5 p.m. Trailheads, including paved bicycle/walking trails and equestrian trails, close at sunset.
The park office is open daily from 7 a.m. to 5 p.m.
Campground 2 and the showerhouse in Campground 1 are closed November through March. Frost-free hydrants and vault toilets are available throughout the park during this time.

Summer Hours (On-Season)
From April through September, the park grounds are open daily from 7 a.m. to 8 p.m. Gates to day-use areas, which would include the off-road vehicle (ORV) riding area, lakes and Pim day-use area, close at 8 p.m. Trailheads, including paved bicycle/walking trails and equestrian trails, close at sunset.
The park office is open daily from 7 a.m. to 8 p.m.
Campground 2 is open from April through October.

Source: MO State Parks