密西根下半岛 （英语：Lower Peninsula of Michigan），简称下半岛 （the Lower Peninsula、"The L.P."），是构成美国密西根州两块陆地之一，全州的政治、经济、文化中心。北为麦基诺水道，南为东为休伦湖，西为密西根湖，南为俄亥俄州和印地安纳州。

因其形状又被称为“The Mitten”（连指手套）、“Below the Bridge”（桥下），有时也称“The L.P.”（相对上半岛的别称“the U.P”而言）。这里的居民有时候会被上半岛的居民戏称为“flat-landers”或“trolls”。

The Lower Peninsula of Michigan is the southern of the two major landmasses of the U.S. state of Michigan. It is surrounded by water on all sides except its southern border, which it shares with Ohio and Indiana. Geographically, the Lower Peninsula has a recognizable shape that many people associate with a mitten, with the mid-eastern region identified as The Thumb. This has led to several folkloric creation myths for the area, one being that it is a hand print of Paul Bunyan, a giant lumberjack and favorite European-American folk character in Michigan. When asked where they live, Lower Peninsula residents may hold out a hand and point to a spot on it to indicate the location. The peninsula is sometimes divided into the Northern Lower Peninsula and Southern Lower Peninsula.