Janesville, Wisconsin
Janesville is a city in Rock County, Wisconsin, with 65,638 residents in 2020. It is in Wisconsin's 1st congressional district. It spans 2 state house districts. Its state senate district is State Senate District 15.
County
| County | Share of residents |
|---|---|
| Rock County | 100% |
Congressional district
| Congressional district | Share of residents |
|---|---|
| Wisconsin's 1st congressional district (WI-01) | 100% |
Elected officials
| Office | Member | Contact | Share of residents |
|---|---|---|---|
| Mayor | Janesville City Council | 608-373-6015 | citywide |
| U.S. Representative (WI-01) | Bryan Steil (R) | 202-225-3031 | 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 15) | Mark Spreitzer (Democratic) | 100% | |
| Assembly Member (Assembly District 44) | Ann Roe (Democratic) | 74% | |
| Assembly Member (Assembly District 43) | Brienne Brown (Democratic) | 26% |
Officials serving now (members of Congress until January 3, 2027). Sources: Mayors: Open States (public domain); State legislators: Open States (public domain); Members of Congress: the @unitedstates project, congress-legislators (CC0).
Local government
- Janesville laws: search for the Janesville, Wisconsin code of ordinances
- Rock County website: https://www.co.rock.wi.us/
- Rock County laws: search for the Rock County, Wisconsin code of ordinances
State legislative districts
| State senate district | Share of residents |
|---|---|
| State Senate District 15 | 100% |
| State house district | Share of residents |
|---|---|
| Assembly District 44 | 74% |
| Assembly District 43 | 26% |
ZIP codes
Percentages mark ZIPs only partly in Janesville: the share of that ZIP's residents living in it.
Get this in your AI agent
Your agent can get Janesville's counties and districts with shares, its ZIP codes (level='zcta'), and its boundary as GeoJSON (get_boundaries). Add https://boundarymcp.com/mcp to Claude, ChatGPT, Cursor or Codex (free, no key; how), then:
related_geographies(id="us:place:5537825")
Janesville here is the Census Bureau's place boundary as of January 1, 2025. Shares are of 2020 Census population. Districts are the maps in force for the November 3, 2026 election.