At the historic Oliver Kelley Farm, the visitor center's roof leaks, and sometimes dozens of students on field trips wait on four crowded bathroom stalls.

"It is a building that is, in essence, worn out," said the site's manager, Bob Quist.

The Minnesota Historical Society is now seeking $10.5 million in state bonding money this legislative session to renovate the farm's visitor center and build several new facilities. It's the society's largest and highest-priority bonding request.

Rep. Nick Zerwas, R-Elk River, is leading the farm's request in the House. Though other bonding requests may make a "bigger splash," he said, the Kelley farm project would have both regional and statewide impact.

"If we're able to look at what bonding is for … I think this meets that test very easily," he said.

The Legislature allocated $300,000 for pre-design work in 2008. It then approved about $9.4 million for a farm renovation in the 2010 bonding bill, but then-Gov. Tim Pawlenty eliminated that sum with a line-item veto.

The Kelley site, a National Historic Landmark, is a preserved 1860s farm that serves visitors and tour groups who want to learn about agricultural history.

About 30,000 Minnesotans visit the farm each year, almost half of them students. But with space constraints at the visitor center and increasing demand for field trips, Quist said the farm has had to turn away hundreds of students each year.

When the center was built in the 1970s, the design plans didn't anticipate thousands of annual visitors, he said.

The new plan accounts for 45,000 visitors per year. It would triple the size of the visitors center and add a new maintenance building, a guest animal shelter for visiting livestock and a multipurpose shelter that could be rented out or give more space to large visiting groups.

This year, Gov. Mark Dayton didn't include state money for the Kelley farm in his bonding proposal. Still, Zerwas said he's optimistic about the House's bonding recommendations.

"It's time to make sure at the farm [that] we maintain the assets, we improve on it and allow it to be at its full capacity," Zerwas said.

Cody Nelson is a University of Minnesota student reporter on assignment for the Star Tribune.