Lanark County

Lanark County is a mostly forested and rocky county in the Ottawa Valley, about an hour west of the city of Ottawa. In many ways, this county represent the natural environment of the entire Ottawa Valley, with a mixtures of forests, fire barrens, wetlands and alvars. You can enjoy a one hour video introduction here.

Lanrk Count is a fine place for outdoor recreation, yet is often overlooked by hikers and naturalists who go instead to Gatineau Park or the Adirondacks.

A brief introduction:

Lanark County has Precambrian rock in the west, as you find in the upper Ottawa Valley (including Algonquin Provincial Park) as well as limestone in the east, as you find in the lower Ottawa Valley (including the City of Ottawa).  There are also extensive areas of marble.

Parts of the county are flat with thick clay deposits that originated more than ten thousand years ago. The western side of Lanark County was flooded by an enormous glacial lake, so these clay areas originated under fresh water. The eastern side of the county was flooded by the Champlain Sea, so many of these deposits come from more saline conditions. The eastern clay plains extend from Lanark County all the way to Montreal. The old shoreline of the Champlain sea can still be found, and is mapped in my guide to the county. A colour soil map for the county is provided later on this page. 

Click to enlarge

When the first Europeans arrived, the area was mainly deciduous forest, but there were also fire barrens and pine ridges, as well as lakes and beaver ponds and extensive swamps.  The history is also typical: indigenous peoples were replaced by Europeans, predominantly Scottish and Irish settlers, who logged the forests and cleared for farms.  On deeper soils there are now prosperous communities, while on shallow and rocky soils, farming collapsed and the forests are recovering. You can read an account of the original forests of Lanark County here.

In spite of two centuries of human settlement, there are still important natural areas left.  These include alvars, rock barrens, and wetlands.  There are also distinctive southern species including five-lined skinks, gray rat snakes and southern flying squirrels. Shagbark hickories have crept as far north as some rocky south-facing hillsides, while a stand of hackberry trees clings to the limestone cliffs along the rapids in Carleton Place. A list of 30 of our most important natural areas, including habitat for species-at-risk, is here.

This page is intended to provide citizens with an introduction to the natural environment of the county, and to encourage the protection of important natural areas. It is also a guide for visitors who wish to explore the natural environment. Below are sources of information on on the ecology of Lanark County, including a guide to our priority natural areas, which I call the thirty Green Gems of Lanark County.

My Resources on Lanark County

A video introduction to the natural environment of Lanark County. I invite you to sit back and enjoy this one hour video recording about the natural environment of the county. If you teach biology or ecology in a local school, you may wish to share this with your class.

The frogs of Lanark County: There are eight species of frog, and one species of toad found in the wetlands of Lanark County. There is even a species of tree frog that does indeed call from trees in May and June. This chart shows when you can hear each species calling. The frog chorus starts each spring with Spring Peepers in April, and ends each summer with Bullfrogs in July. All of these frogs depend upon healthy wetlands and forests.

Ground nesting birds: There are about fifty species of birds in Lanark County that nest on the ground. These native birds are particularly sensitive to human activities. Some, like the whip-poor-will and the black and white warbler, are declining in numbers. These birds illustrate why some natural areas need protection from human recreation or logging during the spring and summer.

My Book

My self-published book Earth, Water, Fire: An Ecological Profile of Lanark County is a solid introduction to the natural heritage and human history of the area.

Find out where to buy it

30 Green Gems

The thirty green gems of Lanark County: priority areas for protection.

Green gems of Lanark County
Click for a larger sized map


Some External Resources

Coexisiting with wetlands and forests: How Much Habitat is Enough?

The Plants of Lanark County by David White

Soil map for Lanark County

Northern half: enlarge
Southern half: enlarge