The 4,300-acre Thermalito Afterbay is a popular hub for fast-paced water sports and extensive motorized watercraft use. The Afterbay accommodates jet skis and high-performance motorized boats with two- and four-stroke motors, offering ample space for high-energy wakeboarding and speed boating.
A diversion pool downstream of Lake Oroville, the Afterbay is also open for swimming, fishing, picnicking, and limited hunting along its 17 miles of shoreline. No-wake speed limits before and after sunset allow for peaceful paddling, swimming and fishing.
Smaller and shallower than Lake Oroville, and larger than the nearby Thermalito Forebay, the Afterbay is located between Highways 70 and 99, easily accessible from Oroville, Chico and Paradise.
Amenities & Features
- Boating Access: A two-lane boat ramp with a floating dock is located on the eastern shoreline at Monument Hill. Multiple undeveloped, dispersed boat-in day-use sites are scattered along the water.
- Monument Hill Day Use Area: The lake’s main recreation hub, featuring a swimming beach, 10 picnic tables, nine BBQs, flush toilets (ADA accessible), and a fish-cleaning station.
- Water-Skiing: Test out your skills on a dedicated course
Trailheads & Access Points
The northern and western shorelines sit within the Oroville Wildlife Area, offering direct access to the Brad Freeman Trail via three distinct points:
- East Hamilton Road: Small gravel parking area (approx. 5 vehicles) with a picnic table.
- Toland Road: Northwest corner of the Afterbay; gated roadside parking only (no facilities).
- Tres Vias: Located 1.5 miles east of Toland Road; features a simple dirt lot and trail connection (no facilities).
Additional Amenities
- Primitive Camping: A handful of basic, primitive campsites are available just north of the Afterbay outlet.
- Model Aircraft Runway: A dedicated paved runway for RC model aircraft is located near North Wilbur Road at the Afterbay Canal.
Other Information
The Department of Water Resources manages the recreation facilities and boat ramps.
