ZIP code 53551: Lake Mills, WI

ZIP code 53551 is in Lake Mills (70% of residents), in Jefferson County, Wisconsin. 30% of its residents live outside city limits. It is in Wisconsin's 5th congressional district. Its state senate districts are State Senate District 16 (97%) and State Senate District 13 (3.4%); its state house districts are Assembly District 46 (97%) and Assembly District 38 (3.4%).

8,920residents (2020 Census)

39.6 sq miland area

1cities and towns

1congressional district

16voting precincts

See it on the map All of Wisconsin

City and county

City or town	Share of ZIP residents
Lake Mills	70%

County	Share of ZIP residents
Jefferson County	100%

Town or county subdivision	Share of ZIP residents
Lake Mills city	70%
Lake Mills town	19%
Aztalan town	4.7%
Milford town	3.4%
Waterloo town	2.5%
Oakland town	0.5%
Jefferson town	0.1%

Congressional district

Congressional district	Share of ZIP residents
Wisconsin's 5th congressional district (WI-05)	100%

Elected officials

Office	Member	Contact	Share of residents
U.S. Representative (WI-05)	Scott Fitzgerald (R)	202-225-5101	100%
U.S. Senator	Ron Johnson (R)	202-224-5323 · contact form	statewide
U.S. Senator	Tammy Baldwin (D)	202-224-5653 · contact form	statewide
State Senator (State Senate District 16)	Melissa Ratcliff (Democratic)		97%
State Senator (State Senate District 13)	John Jagler (R)		3.4%
Assembly Member (Assembly District 46)	Joan Fitzgerald (Democratic)		97%
Assembly Member (Assembly District 38)	Will Penterman (R)		3.4%

Officials serving now (members of Congress until January 3, 2027). Sources: State legislators: Open States (public domain); Members of Congress: the @unitedstates project, congress-legislators (CC0).

Local government

Lake Mills website: http://www.ci.lake-mills.wi.us/
Lake Mills laws: search for the Lake Mills, Wisconsin code of ordinances
Jefferson County website: https://www.jeffersoncountywi.gov/
Jefferson County laws: search for the Jefferson County, Wisconsin code of ordinances

State legislative districts

State senate district	Share of ZIP residents
State Senate District 16	97%
State Senate District 13	3.4%

State house district	Share of ZIP residents
Assembly District 46	97%
Assembly District 38	3.4%

Voting precincts

16 voting precincts overlap ZIP 53551. Map them, with each precinct's share of the ZIP's residents.

Get this in your AI agent

Your agent can get these cities, counties, districts and precincts with their shares, and their GeoJSON boundaries, from Boundary Atlas. Add https://atlas-production-d344.up.railway.app/mcp to Claude, ChatGPT, Cursor or Codex (free, no key; how), then:

related_geographies(id="us:zcta:53551")

ZIP 53551 here is the Census Bureau's ZIP Code Tabulation Area, which approximates the USPS ZIP Code; PO-box-only ZIPs have none. Districts are the maps in force for the November 3, 2026 election.