[1] Lenawee County comprises the Adrian, MI Micropolitan Statistical Area.

Lenawee County is home to the Potawatomi, Ottawa, Chippewa, Iroquois, Miami, Sauk, Fox, Mascoutens and Huron tribes.

[4] The county owes its formation to the 1807 Treaty of Detroit, by which the Ottawa, Ojibwe (called Chippewa by the Americans); Wyandot and Potawatomi nations ceded their claims to the United States of their traditional territories in today's southeast Michigan.

They began to collaborate and organize a confederacy of resistance, led by Chief Tecumseh (Shawnee).

[6] The United States won the Battle of the Thames in 1813, defeating the British and their allies.

In 1830, President Andrew Jackson signed the Indian Removal Act to authorize the government to relocate Indigenous peoples from territories east of the Mississippi River and move them west, to what became known as Indian Territory (and later Oklahoma).

[1] The county's name was a neologism created by Henry Rowe Schoolcraft, a US Indian agent in the region who later became a prominent ethnologist.

While working in Michigan, he named several of the newly organized counties in the area, all neologisms.

Scholars debate whether its origins lie in the Lenape language leno or lenno, meaning "male," or the Shawnee lenawai.

The county government operates the jail, maintains rural roads, operates the major local courts, records deeds, mortgages, and vital records, administers public health regulations, and participates with the state in the provision of social services.

The county board of commissioners controls the budget and has limited authority to make laws or ordinances.

In Michigan, most local government functions—police and fire, building and zoning, tax assessment, street maintenance, etc.—are the responsibility of individual cities and townships.

In between her leaving office in 2016 and returning in 2024 Lenawee was represented by Bronna Kahle and Dale Zorn who are also both Republicans and prior to her first term the district was successively represented by brothers Doug and Dudley Spade, both Democrats.

Most of Lenawee is part of the 16th Senate District, represented by Joe Bellino of Monroe, Michigan.