Lake Lillian is the name of several places in the United States:
;Lakes
* Lake Lillian (Florida), in Highlands County
* Lake Lillian (Kandiyohi County, Minnesota)
* Lake Lillian (Washington), in the Alpine Lakes Wilderness
;Cities and townships
* Lake Lillian, Minnesota, a small city in Kandiyohi County
* Lake Lillian Township, Kandiyohi County, Minnesota
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