The geographic distribution of humid continental ranges particularly from the upper most east side of North America, most of Europe and Northeastern of Asia. Notice how most almost everything I said was either north, east, or both. This is because the geographic distribution of a Humid Continental lies mostly on East coasts, and interiors of the upper-middle-latitude of continents, hence North and East. With this being said, examples include countries such as: Russia, Poland, Ukraine, Lativa, etc.
Down below are some of the images of places included, but not limited to the humid continental region. (1. New York 2.Russia 3. Iowa 4.Pooland 5.Maine 6.Ukraine)