Chicago - Democrats took control of six state legislative chambers to two for Republicans, reversing off-year voting trends and strengthening their position at the state houses.
Preliminary results showed that Democrats netted approximately 45 seats and seized control of the Wisconsin Senate, North Carolina House, New Hampshire Senate, Indiana House and both chambers in Washington State, according to projections by the National Conference of State Legislatures.
Republicans took control of the Michigan House and the Minnesota House.
The net gain for Democrats gave them control of 54 state legislative chambers to 44 for Republicans. Previously, Democrats held majorities in 50 chambers and the Republicans in 48.
Democrats now control both legislative chambers in 21 states, with Republicans dominating both chambers in 16 states.
Prior to the election, Democrats controlled both chambers in 20 states, while Republicans dominated in 19 states, with 10 state legislatures split between the two parties.
Nebraska's single legislative chamber is non-partisan.
The net gain for Democrats on the state level mirrored the success of the party in congressional races this year. In both cases, Democrats broke long-standing trends of off-year losses for the party that controls the White House.
There are 7,424 state legislators in the United States. Normally 6,200 to 6,400 seats are up for election in mid-term races. According to the legislature group, 83 per cent of legislative seats were contested on Tuesday.
The election will give Democrats control of both chambers in Alabama, Arkansas, California, Connecticut, Georgia, Kentucky, Hawaii, Louisiana, Maine, Maryland, Massachusetts, Missouri, Mississippi, New Mexico, North Carolina, Oklahoma, Rhode Island, Tennessee, Vermont, Washington and West Virginia.
Republicans will control both chambers in Alaska, Arizona, Colorado, Florida, Idaho, Iowa, Kansas, Michigan, Montana, New Jersey, North Dakota, Ohio, Pennsylvania, South Dakota, Utah and Wyoming.