The painting "Muskoka River, circa 1940" by George Thomson offers a panoramic view of the Muskoka River, capturing the rugged natural beauty of the Canadian landscape. The river meanders through the composition, with its water reflecting the sky and creating a sense of movement that draws the viewer's eye through the scene.

The landscape is depicted with a mix of evergreen and deciduous trees, suggesting the diversity of the Muskoka region's flora. The trees are painted with a level of detail that showcases their textures and the variety of colors, especially in the foliage.

In the distance, a collection of small buildings can be seen, likely cottages or boathouses, which are characteristic of the Muskoka area, known for its lakeside retreats. The use of muted, natural tones for the buildings indicates that they are a harmonious part of the landscape rather than dominant features.

The sky is rendered with a combination of soft blues and whites, with fluffy clouds that suggest a lively, changing weather pattern. The overall light in the painting suggests either early morning or late afternoon, times when the sun's angle highlights the contours of the land and water.

Thomson's brushwork is both detailed and impressionistic, allowing for a sense of realism without sacrificing the painterly quality of the work. The Muskoka River, with its serene waters and surrounding landscape, is brought to life through his skilled use of color and light, offering a timeless glimpse of this beloved Canadian region.