Places We Protect

Ottawa Bluffs


from atop TNC's Ottawa Bluffs Preserve.
View of the Minnesota River from atop TNC's Ottawa Bluffs Preserve. © Nancy Johnson

Visitors to the top of the bluff will find themselves next to an American Indian burial mound.



Visitors to the top of the bluff on the west side of the preserve will not only be rewarded with a fine view of the Minnesota River Valley, but will also find themselves next to an American Indian burial mound. Ottawa Bluffs can be a great place to see the pasque flower, the first prairie flower of the spring. These beauties can be found on the south-facing slopes in the prairie opening, especially toward the tops of the rises. Look for them in early April, as soon as the ground starts thawing.

Why TNC Selected This Site

Oak savannas are one of the most endangered ecological communities in Minnesota.

What TNC Has Done/Is Doing

Ottawa Bluffs was purchased by the Conservancy in 1975 to protect a remnant of the Minnesota River bluffs. Because of the extensive invasion by woody vegetation, a concerted effort is underway to restore the site to its pre-settlement conditions. While the prairie openings have been managed by prescribed fire since the Conservancy acquired the site, the frequency and intensity of these burns has been insufficient to set back this encroachment. 

To remedy this, volunteers have been working at Ottawa Bluffs  to remove trees and brush from selected areas, and to bring the role of fire back to the woody areas of the preserve. This work consists mostly of cutting eastern red cedar and European buckthorn. Much of this work is done during the winter, when cool temperatures are conducive to physical labor and when the cuttings can be safely disposed of by burning. Additionally, the volunteers harvest prairie seeds from the remnants to plant in the cleared areas, in order to facilitate the return of the savanna and the prairie. The use of these techniques is helping to restore Ottawa Bluffs' oak savanna and the diversity of species that live here.




62 acres

Explore our work in this region

Please respect the Indian mound and do not disturb it. Consider that, when the mound was constructed (hundreds of years ago), the countryside was a mixture of prairie, oak savanna, and woodland, in all directions.

What to See: Plants

In the prairie openings can be found a variety of forbs and grasses. One of the milkvetches is found here, though it is a much more common plant in the drier, short grass prairies to the west. The dominant tall grasses at Ottawa are Indian grass and big bluestem. During late August and September, they dominate the prairie-scape. Other shorter grasses include little bluestem, dropseed, porcupine, hairy gramma, and side-oats gramma. Forbs include pasque flower, prairie turnip, prairie plum, birds-foot violet, blue-eyed grass, Indian turnip, purple prairie clover, prairie larkspur, spider wort, lead plant, blazing star, round headed bush clover, silky aster and aromatic aster.

What to See: Animals

Ottawa Bluffs harbors a number of animal species, including the harvest mouse (a typically western species only found in the southern part of Minnesota) and jumping mouse. A sizable flock of wild turkeys can be seen in the area. The bluff line is a favorite soaring space for raptors, which are frequently seen cruising over the preserve.

For more information on visiting this and other Minnesota preserves, check out our Preserve Visitation Guidelines.

Volunteer Workdays

Workdays take place on Saturdays throughout the fall and winter seasons. Winter workdays will focus on tree and brush removal and will be held on November 10, December 1 and December 15.

Please read the list of things you should know before you volunteer at TNC preserves in Minnesota.

All workdays start at 10:00 a.m. and end around 3:00 p.m. (later if you'd care to stay). Please bring a lunch, plenty of beverage, appropriate (sturdy) foot wear and work gloves. Leather gloves work best. Dress in layers with an eye toward the weather. Rain, snow or shine, we will be out there. Thunderstorms may make us head for the cars, but if there is a chance the weather will clear, we will resume the workday.

For information about upcoming Ottawa Bluffs workdays, email Bill Ramsden ( to sign up for the Ottawa Bluffs volunteer e-newsletter.