This chart shows the trends in the partisan composition of the various state legislatures in the United States. In most cases the data point for each year is July 1st, a time when few elections are scheduled. Most states hold legislative elections in the even numbered years, so the data points below are near the end of the term for most states. Nebraska is not included in the national summaries below.
| National summary | 2011 | 2010 | 2008 | 2006 | 2004 | |
|---|---|---|---|---|---|---|
| Lower Houses | R 30-18, 1 tie | D 33–16 | D 30–19 | R 25–23, 1 tie | R 26–23 | |
| Upper Houses | R 28-20, 1 Coal. | D 28–20, 1 Coal. | D 28–20, 1 Coal. | 24–24, 1 tie | R 27–21, 1 tie | |
| Both houses controlled by one party | R 25-15, 9 split | D 27–14, 8 split | D 23–13, 13 split | R 20–19, 10 split | R 21–17, 11 split | |
| Governor and both houses controlled by one party | R 21-11, 17 divided | D 16–9, 24 divided | D 14–9, 26 divided | R 12–8, 29 divided | R 12–8, 29 divided | |
| State | House | 2011 | 2010 | 2008 | 2006 | 2004 |
| Alabama | House of Representatives | R 66–39 | D 60–45 | D 62–43 | D 63–42 | D 64-41 |
| Senate | R 22–12, 1 Ind. | D 21–13, 1 Ind. | D 22–13 | D 25–10 | D 25-10 | |
| Alaska | House of Representatives | R 24–16 | R 22–18 | R 23–17 | R 26–14 | R 27-13 |
| Senate | Coal. 16–4 | Coal. 16–4 | Coal. 15–5 | R 12–8 | R 12-8 | |
| Arizona | House of Representatives | R 40–20 | R 36–24 | R 33–27 | R 38–22 | R 39-20, 1 Ind. |
| Senate | R 21–09 | R 18–12 | R 17–13 | R 18–12 | R 17-13 | |
| Arkansas | House of Representatives | D 55–44, 1 vac. | D 72–28 | D 75-25 | D 72-28 | D 70-30 |
| Senate | D 20–15 | D 27–8 | D 27-8 | D 27-8 | D 27-8 | |
| California | Assembly | D 52–28 | D 50–29, 1 Ind. | D 48-32 | D 48-32 | D 48-32 |
| Senate | D 25–15 | D 26–14 | D 25-15 | D 25-15 | D 25-15 | |
| Colorado | House of Representatives | R 33-32 | D 38–27 | D 40-25 | D 35-30 | R 37-28 |
| Senate | D 20–15 | D 20–15 | D 20-15 | D 18-17 | R 18-17 | |
| Connecticut | House of Representatives | D 99-52 | D 114–37 | D 107-44 | D 99-52 | D 95-56 |
| Senate | D 22-14 | D 24–12 | D 23-13 | D 24-12 | D 21-15 | |
| Delaware | House of Representatives | D 26-15 | D 24–16, 1 Vac. | R 22-19 | R 26-15 | R 29-12 |
| Senate | D 14-7 | D 15–6 | D 13-8 | D 13-8 | D 13-8 | |
| Florida | House of Representatives | R 81-39 | R 76–44 | R 78-42 | R 85-35 | R 81-39 |
| Senate | R 28-12 | R 26–14 | R 26-14 | R 26-14 | R 26-14 | |
| Georgia | House of Representatives | R 116-63, 1 Ind. | R 105–74, 1 Ind. | R 107-73 | R 100-79, 1 Ind. | D 107-72, 1 Ind. |
| Senate | R 36-20 | R 34–22 | R 34-22 | R 34-22 | R 30-26 | |
| Hawaii | House of Representatives | D 43-8 | D 45–6 | D 44-7 | D 41-10 | D 36-15 |
| Senate | D 24-1 | D 23–2 | D 21-4 | D 20-5 | D 20-5 | |
| Idaho | House of Representatives | R 57-13 | R 52–18 | R 51-19 | R 57-13 | R 54-16 |
| Senate | R 28–7 | R 28–7 | R 28-7 | R 28-7 | R 28-7 | |
| Illinois | House of Representatives | D 64-54 | D 70–48 | D 67-51 | D 65-53 | D 66-52 |
| Senate | D 35-24 | D 37–22 | D 37-22 | D 31-27 1 Ind. | D 32-26, 1 Ind. | |
| Indiana | House of Representatives | R 60-40 | D 52–47, 1 Ind. | D 51-49 | R 52-48 | D 51-49 |
| Senate | R 37-13 | R 33–17 | R 33-17 | R 33-17 | R 32-18 | |
| Iowa | House of Representatives | R 60-40 | D 56–44 | D 53-47 | R 51-49 | R 54-46 |
| Senate | D 26-24 | D 31–19 | D 30-20 | 25-25 | R 29-21 | |
| Kansas | House of Representatives | R 92-33 | R 77–48 | R 78-47 | R 83-42 | R 80-45 |
| Senate | R 32-8 | R 31–9 | R 30-10 | R 30-10 | R 30-10 | |
| Kentucky | House of Representatives | D 58-42 | D 65–35 | D 64-36 | D 56-44 | D 64-36 |
| Senate | R 22–15, 1 Ind. | R 22–15, 1 Ind. | R 21-16, 1 Ind. | R 21-16, 1 Ind. | R 22-16 | |
| Louisiana | House of Representatives | R 55-46, 4 Ind. | D 52–50, 3 Ind. | D 53-50, 2 Ind. | D 67-37, 1 Ind. | D 67-37, 1 Ind. |
| Senate | R 22-17 | D 22–15, 2 Ind. | D 23-16 | D 24-15 | D 25-14 | |
| Maine | House of Representatives | R 78-72, 1 Ind. | D 95–55, 1 Ind. | D 90-59, 2 Ind. | 73-73, 4 Ind, 1 Green | D 82-66, 4 Ind, 1 Green |
| Senate | R 20-14, 1 Ind. | D 20–15 | D 18-17 | D 19-16 | D 18-17 | |
| Maryland | House of Delegates | D 98-43 | D 104–36, 1 Ind. | D 104-37 | D 98-43 | D 98-43 |
| Senate | D 35-12 | D 33–14 | D 33-14 | D 33-14 | D 33-14 | |
| Massachusetts | House of Representatives | D 128-31, 1 Ind. | D 143–16, 1 Ind. | D 141-19 | D 139-21 | D 136-23, 1 Ind. |
| Senate | D 36-4 | D 35–5 | D 35-5 | D 34-6 | D 33-7 | |
| Michigan | House of Representatives | R 63-47 | D 67–43 | D 58-52 | R 58-49, 3 Vac. | R 63-46, 1 Vac. |
| Senate | R 26-12 | R 21–17 | R 21-17 | R 22-16 | R 22-16 | |
| Minnesota | House of Representatives | R 72-62 | DFL 87–47 | DFL 85-48, 1 Ind. | R 68-66 | R 81-53 |
| Senate | R 37-30 | DFL 46–21 | DFL 45-22 | DFL 37-29, 1 Ind. | D 35-31, 1 Ind. | |
| Mississippi | House of Representatives | D 69-53 | D 74–48 | D 75-47 | D 75-47 | D 76-46 |
| Senate | R 27-24, 1 Ind. | D 27–25 | D 27-25 | D 28-24 | D 29-23 | |
| Missouri | House of Representatives | R 106-57 | R 89–74 | R 92-71 | R 96-66, 1 Vac. | R 90-73 |
| Senate | R 26-8 | R 23–11 | R 20-14 | R 23-11 | R 20-14 | |
| Montana | House of Representatives | R 68-32 | D 50–50 | R 50-49, 1 Const. | 50-50 | R 53-47 |
| Senate | R 28-22 | R 27–23 | D 26-24 | D 26-24 | R 29-21 | |
| Nebraska | Unicameral and non–partisan Senate with 49 members | |||||
| Nevada | Assembly | D 26-16 | D 28–14 | D 27-15 | D 26-16 | D 23-19 |
| Senate | D 11-10 | D 12–9 | R 11-10 | R 12-9 | R 13-8 | |
| New Hampshire | House of Representatives | R 294-103, 3 vac. | D 225–175 | D 239-161 | R 247-152 1 Vac. | R 279-121 |
| Senate | R 19-5 | D 14–10 | D 14-10 | R 16-8 | R 18-6 | |
| New Jersey | General Assembly | D 47–33 | D 47–33 | D 48-32 | D 49-31 | D 47-33 |
| Senate | D 23–17 | D 23–17 | D 23-17 | D 22-18 | D 22-18 | |
| New Mexico | House of Representatives | D 37-33 | D 45–25 | D 42-28 | D 42-28 | D 43-27 |
| Senate | D 27-15 | D 27–15 | D 24-18 | D 24-18 | D 24-18 | |
| New York | Assembly | D 92-51, 6 vac. | D 108–42 | D 108-42 | D 105-45 | D 102-47, 1 Vac. |
| Senate | R 32-30 | D 32–30 | R 32-30 | R 35-27 | R 37-24, 1 Vac. | |
| North Carolina | House of Representatives | R 67-52-1 | D 68–52 | D 68-52 | D 63-57 | R 61-59 |
| Senate | R 31-19 | D 30–20 | D 31-19 | D 29-21 | D 27-23 | |
| North Dakota | House of Representatives | R 69-25 | R 58–36 | R 61-33 | R 67-27 | R 66-28 |
| Senate | R 35-12 | R 26–21 | R 26-21 | R 32-15 | R 31-16 | |
| Ohio | House of Representatives | R 59-40 | D 53–46 | R 53-46 | R 60-38, 1 Vac. | R 62-37 |
| Senate | R 23-10 | R 21–12 | R 21-12 | R 22-11 | R 22-11 | |
| Oklahoma | House of Representatives | R 70-31 | R 62–39 | R 57-44 | R 57-44 | D 53-48 |
| Senate | R 32-16 | R 26–22 | D 24-24 | D 25-22 | D 28-20 | |
| Oregon | House of Representatives | 30-30 | D 36–24 | D 31-29 | R 33-27 | R 35-25 |
| State Senate | D 16-14 | D 18–12 | D 18-11, 1 Ind. | D 18-12 | 15-15 | |
| Pennsylvania | House of Representatives | R 112-91 | D 104–99 | D 102-101 | R 109-93, 1 Vac. | R 109-94 |
| Senate | R 30–20 | R 30–20 | R 29-21 | R 29-20, 1 Vac. | R 29-21 | |
| Rhode Island | House of Representatives | D 65-10 | D 69–6 | D 60-15 | D 60-15 | D 63-11, 1 Ind. |
| Senate | D 29-8-1 | D 33–4, 1 Ind. | D 33-5 | D 33-5 | D 32-6 | |
| South Carolina | House of Representatives | R 76-47-1 | R 71–53 | R 73-51 | R 73-51 | R 73-51 |
| Senate | R 27-19 | R 27–19 | R 26-20 | R 26-20 | R 25-21 | |
| South Dakota | House of Representatives | R 50-19-1 | R 46–24 | R 50-20 | R 51-19 | R 49-21 |
| Senate | R 30-5 | R 20–14, 1 Ind. | R 20-15 | R 25-10 | R 26-9 | |
| Tennessee | House of Representatives | R 64-34-1 | R 50–48, 1 Ind. | D 53-46 | D 53-46 | D 54-45 |
| Senate | R 20-13 | R 19–14 | R 16-16, 1 Ind. | R 17-15, 1 Vac. | D 18-15 | |
| Texas | House of Representatives | R 101-49 | R 76–74 | R 79-71 | R 86-64 | R 88-62 |
| Senate | R 19–12 | R 19–12 | R 20-11 | R 19-12 | R 19-12 | |
| Utah | House of Representatives | R 58-17 | R 53–22 | R 55-20 | R 56-19 | R 56-19 |
| Senate | R 22-7 | R 21–8 | R 21-8 | R 21-8 | R 22-7 | |
| Vermont | House of Representatives | D 96–46-8 | D 95–48 R, 5 Prog, 2 Ind. | D 93-49, 6 Prog. 2 Ind. | D 83-60, 6 Prog, 1 Ind. | R 73-71, 4 Prog, 2 Ind. |
| Senate | D 22–8 | D 22–7, 1 Prog. | D 23-7 | D 21-9 | D 19-11 | |
| Virginia | House of Delegates | R 59–39, 2 Ind. | R 59–39, 2 Ind. | R 53-45, 2 Ind. | R 56-40, 3 Ind, 1 Vac. | R 61-37, 2 Ind. |
| Senate | D 22–18 | D 22–18 | D 21-19 | R 23-17 | R 24-16 | |
| Washington | House of Representatives | D 55-42 | D 64–34 | D 63-35 | D 56-42 | D 52-46 |
| Senate | D 27-22 | D 31–18 | D 32-17 | D 26-23 | R 25-24 | |
| West Virginia | House of Delegates | D 65-35 | D 79–21 | D 72-28 | D 68-32 | D 69-31 |
| Senate | D 28–6 | D 28–6 | D 23-11 | D 21-13 | D 24-10 | |
| Wisconsin | Assembly | R 59-38-1, 1 vac. | D 52–46, 1 Ind. | R 52-47 | R 59-39, 1 Vac. | R 59-40 |
| Senate | R 19-14 | D 18–15 | D 18-15 | R 19-14 | R 18-15 | |
| Wyoming | House of Representatives | R 50-10 | R 41–18 | R 43-17 | R 46-14 | R 45-15 |
| Senate | R 26-4 | R 23–7 | R 23-7 | R 23-7 | R 20-10 | |
| National summary | 2011 | 2010 | 2008 | 2006 | 2004 | |
| Lower Houses | R 61%-37%, 2% tie | D 67%-33% | D 61%-39% | R 51%-47%, 2% tie | R 53%-47% | |
| Upper Houses | R 57%-41%, 2% tie | D 57%-41%, 2% Coal. | D 57%-41%, 2% Coal. | 49%-49%, 2% tie | R 55%-43%, 2% tie | |
| Both houses controlled by one party | R 51%-31%, 18% split | D 55%–29%, 16% split | D 47%–27%, 27% split | R 41%–39%, 20% split | R 43%–35%, 22% split | |
| Governor and both houses controlled by one party | R 43%-22%, 35% divided | D 33%–18%, 49% divided | D 29%–18%, 53% divided | R 24%–16%, 59% divided | R 24%–16%, 59% divided | |
See also List of United States state legislatures