Located within the Styxie, San Joaquin is a land comprised of three regions: Western, Central, and Eastern San Joaquin. Western San Joaquin is flat, with much of it lying within the valley of the province's namesake, while central San Joaquin is accentuated with the Sierra Nevada mountain range, and eastern San Joaquin an alternation of hills and valleys in the Great Basin. The province includes one of Northern Sierra's most important water sources: the Hetch Hetchy and the northern part of the internationally renowned Yosemite National Park.