Tracking turnover in the state legislatures is often painfully slow. But already the GOP has put historic-level legislative gains on the scoreboard.

According to the National Conference of State Legislatures (NCSL) and Governing's own research, Republicans took over at least 19 Democratic-held chambers, with another Democratic chamber slipping into a tie. As many as four additional chambers could shift to the GOP in the coming days, as ballot counting proceeds.

Tim Storey, a political analyst with NCSL, wrote today that the GOP is near a high-water mark for legislative seats that dates back to 1928. "This could give the GOP a dramatic advantage in the redistricting cycle that will start in just a few short months," Storey wrote.

The legislative switches, he noted, include a historic win in the Minnesota Senate where Republicans will be in the majority for the first time ever. Republicans will now control the Alabama Legislature for the first time since Reconstruction, while the GOP will lead the North Carolina General Assembly for the first time since 1870.

Here is the full list of Republican takeovers so far: Alabama Senate and House, Colorado House (though Democrats aren't conceding yet), Indiana House, Iowa House, Maine Senate and House, Michigan House, Minnesota Senate and House, Montana House (chamber had previously been tied), New Hampshire Senate and House, North Carolina Senate and House, Ohio House, Pennsylvania House and Wisconsin Senate and House.

One chamber moved from Democratic control into a tie: Oregon House.

The chambers where control is not yet certain are: the Iowa, New York, Oregon and Washington senates.

All told, the GOP notched six Senate pickups and 13 House pickups, a number that could go as high as 10 Senate pickups, if all the remaining chambers go the Republicans' way.

Even without counting the chambers still in question, the GOP chalked up historic gains. They are on par with 1994, when the Democrats lost 20 chambers to the Republicans and one to a tie, without gaining a single chamber; and the post-Watergate election of 1974, when the Republicans lost 21 chambers to the Democrats and two to ties, while gaining only one from the Democrats.

The one-sided GOP gains were not a surprise. Governing had counted 25 Democratic chambers as being in play on election eve, compared to just one GOP-held chamber and two tied chambers. We had set the range of possible GOP net pickups at four to 12 Senate chambers and seven to 15 House chambers. Regardless of how the final chambers play out, the final number will be comfortably within that range.

On a chamber-by-chamber basis, our ratings were broadly accurate, but a few chambers that we hadn't considered "in play" caught us by surprise. We had rated the Maine House, the Minnesota Senate and the Oregon House as Likely Democratic, meaning the chambers were not "in play" even though they ultimately flipped control.

Still, each of the other 21 chambers that either have shifted or could shift were rated as being "in play." And only one of those 21 chambers had been predicted to lean in the direction opposite of the way it eventually went (the Minnesota House, which we'd called lean Democratic).

In the previous four election cycles since this author has been handicapping the legislatures, one chamber not deemed "in play" flipped during the election in 2002, 2004 and 2006, and none did so in 2008. However, the total number of flipping chambers was significantly bigger this year.

As NCSL's Karl Kurtz noted, GOP gains were not limited to takeovers. They also gained in chambers where they were already in control.

The GOP picked up 24 seats in the Texas House, plus approximately 16 in the Missouri House, 15 in the Kansas House, 14 in the North Dakota House, nine in the Wyoming House and eight in the Oklahoma House.

"Republicans gained seats in virtually every state," Kurtz wrote. "The change was unidirectional. The only state in which Democrats appear to have made a net gain in both chambers combined is Delaware, where they netted one seat."

Indeed, Delaware was one of the rare bright spots for the Democrats, perhaps due to the backlash against U.S. Senate candidate Christine O'Donnell.

The Democrats could have lost -- but did not lose -- control of several other chambers that were considered in play on Election Night. Barring late-breaking developments, these include the Colorado Senate, the Illinois House, the Nevada Senate and the Washington House.