Louisiana State Senate seat · lines in effect since 2022
Louisiana Senate District 21
A district of about 125,000 people, 25% Black, 16% of adults with a bachelor's degree. It votes R+40.7 relative to the nation for president.
2023 runoff
Nov 18, 2023- Robert Allain (R) · won59.0%
- Henry "Bo" LaGrange (R)41.0%
Source: Louisiana Secretary of StateUpdated Sep 30, 2026, 1:09 PM ET
Where it sits among all 38 seats
Every Louisiana State Senate seat by partisan lean, from most Democratic to most Republican. Lean is the seat's presidential vote on current lines, relative to the nation.
Democratic
Source: 99chambers: 2024 and 2020 presidential results on current lines, relative to the nation (2024 weighted 3:1)Updated Oct 16, 2026, 5:19 AM ET
Every election for this seat
17 races since 1968; the seat changed party 1 time. District numbers are redrawn after each census: each group is one set of lines.
| Year | Winner | Runner-up | Won by |
|---|---|---|---|
| Lines first used in 2022 | |||
| 2023 runoff | Robert Allain (R) | Henry "Bo" LaGrange (R) | 18.0 |
| 2023 | Robert Allain (R) | Henry "Bo" LaGrange (R) | 12.4 |
| Lines first used in 2012 | |||
| 2019 | R. L. Allain II (R) | — | Unopposed |
| 2015 | R. L. Allain II (R) | — | Unopposed |
| Lines first used in 2002 | |||
| 2011 | R. L. Allain II (R)Flip | Darrin Guidry (R) | 2.7 |
| 2007 | D. A. Gautreaux (D) | Clayton D. Diaz (R) | 41.9 |
| 2003 | D. A. Gautreaux (D) | Eddie Albares (D) | 76.5 |
| Lines first used in 1992 | |||
| 1999 | D. A. Gautreaux (D) | Mike Domino (D) | 26.2 |
| 1995 | John Siracusa (D) | Johnny Johnson (R) | 4.0 |
| Lines first used in 1982 | |||
| 1991 | M. J. Foster (D) | Eddie Albares (D) | 71.0 |
| 1987 | M. J. Foster (D) | Anthony J. Guarisco Jr. (D) | 28.0 |
| 1983 | Anthony J. Guarisco Jr. (D) | John L. Haydel (D) | 18.4 |
| Lines first used in 1972 | |||
| 1979 | Anthony J. Guarisco Jr. (D) | — | Unopposed |
| 1975 runoff | Anthony J. Guarisco Jr. (D) | Elward T. Brady (D) | 5.9 |
| 1975 | No winner recorded | Anthony J. Guarisco Jr. (D) | — |
| 1972 | Carl W. Bauer (D) | — | Unopposed |
| Lines first used in 1962 | |||
| 1968 | William J. Guste · Charles G. Smither (D) | — | Unopposed |
Primaries: 1968 Democratic primary runoff · 1967 Democratic primary
Won by: the winner's lead over the runner-up, in points of the vote. Source: 99chambers results archive (MEDSL, Klarner, state election offices)
Districts that overlap District 21
The state's districts in other chambers that share residents with this one, and the share of District 21's area in each.
Who lives here, compared
Grey bars show the spread of all 38 seats. Small marks are other seats in Louisiana. The black marker is District 21.
Lowest of 38 seats.
Higher than 81% of seats.
Higher than 54% of seats.
Lower than 54% of seats.
Lower than 51% of seats.
Less dense than 73% of seats.
Source: Census Bureau, American Community Survey 2020–2024 5-year estimates, allocated to current linesUpdated Oct 13, 2026, 5:06 AM ET
Seats most like this one
Nearest seats on demographics, density and lean.
District 2825% BlackR+50.1Not up in 2026District 12
23% Black · 21% college gradsR+47.2Not up in 2026District 31
26% Black · 23% college gradsR+44.8Not up in 2026District 22
26% Black · 24% college gradsR+41.4Not up in 2026
Source: Census Bureau, American Community Survey 2020–2024 5-year estimates, allocated to current lines; 99chambers: 2024 and 2020 presidential results on current lines, relative to the nation (2024 weighted 3:1)Updated Oct 16, 2026, 5:19 AM ET