Grand Mesa is where Blake took me the first time I ever visited him and his family in Grand Junction! To me, it is heaven on Earth, one of the most beautiful sites I have ever seen! Grand Mesa is the largest flat-topped mountain in the world. It has an area of about 500 square miles (1,300 km2) and stretches for about 40 miles (60 km) east of Grand Junction between the Colorado River and the Gunnison River, its tributary to the south.