DENVER — Federal wildlife managers have dramatically increased the amount of land they want to designate as critical habitat for the Canada lynx, a threatened species.

The U.S. Fish and Wildlife Service said Thursday it wants to designate nearly 43,000 square miles in six states.

That’s more than 20 times the 1,800 square miles in three states the agency proposed in late 2006.

The agency reconsidered its earlier rulings about the lynx and seven other species after allegations that Julie MacDonald, a deputy assistant secretary of the interior, interfered in the decisions. She has resigned.

States where land would now be designated as critical lynx habitat are Idaho, Maine, Minnesota, Montana, Washington and Wyoming.

Canada lynx have already been reintroduced in southwestern Colorado, and some of the animals have found their way to the Independence Pass area east of Aspen and elsewhere in the central mountains. One was spotted recently in the Summit County backcountry.

In 2000, the Canada lynx was designed a threatened species under the Endangered Species Act. Lynx are medium-sized cats, generally measuring 30 to 35 inches long and weighing 18 to 23 pounds. They have tufts on their ears, short, black-tipped tails, and large, well-furred feet and long legs for traversing snow.

The public can comment on the habitat proposal until April 28. Comments can be submitted at www.regulations.gov or mailed to the Division of Policy and Directives Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax Drive; Suite 222; Arlington, VA 22203.