Mazama Village Campground (early June–mid-Oct., $21 tents, $25–27 RVs), seven miles south of the rim, has 200 sites, restrooms with showers, and a dump station. A limited number of campsites can be reserved; call 888/774-2728 or use the reservation form at www.craterlakelodges.com [1].
Lost Creek Campground (mid-July–early Oct.), located on the eastern section of Rim Drive, has 16 sites, water, and pit toilets. Neither campground has hookups. Contact the park superintendent (541/594-3100) for more information. Foot traffic in the backcountry is light, so you can set up camp wherever you like in the remote areas surrounding Crater Lake [2].
Links:
[1] http://www.craterlakelodges.com
[2] http://www.moon.com/destinations/oregon/southern-oregon/crater-lake-national-park