a canyon, gorge or vale
The river that flows through the city is 100 meters wide.
The long wide river valley from Minnesota to Louisiana is called the Mississippi River Valley. The Mississippi River runs through multiple states, including Minnesota, Wisconsin, Iowa, Illinois, Missouri, Kentucky, Tennessee, Arkansas, Mississippi, and Louisiana. It is one of the longest rivers in North America.
A wide river valley is called a vale. In Scotland, a wide and flat river valley is also called a strath.
An estuary.
The River Mersey is between 12 metres and 20 metres wide, depending on which point it's measured as it flows through Stockport.
Ganges River is 200-400 miles wide
A small, secluded, and often wooded valley is known as a dell or in Scotland as a glen. A wide, flat valley through which a river runs is known in Scotland as a strath. (from https://en.wikipedia.org/wiki/Valley)
whether they are deep or wide, slow or fast flowing, shallow or steep gradient, a river flows in a channel
Congaree River is a short but wide river in South Carolina in the United States.It flows for only 47 miles (78 km).
a dale
that's easy its the st. johns river it go through northern Florida
From atop the mountain, I could see the entire valley below.