This area has deep soils that support northern hardwoods and spruce-fir forests. Similar to the Berkshire Highlands with its common northern hardwoods, but lacks spruce-fir and harbors transition hardwoods. Lakes and ponds are relatively abundant. This area drains to the Westfield and Connecticut River basins. Hills are sometimes quite steep.
Surface waters are highly alkaline.
This area drains to the Deerfield and Connecticut River basins. This area includes the most hilly areas of the central upland with a few high monadnocks and mountains. Forests are transition hardwoods and some northern hardwoods. Forested wetlands are common. Surface waters are acidic.