At 1,013km (629 miles) the Loire is France's longest river, though not all of it is navigable. Its main tributary is the 396-km (246-mile) Cher. The Loire rises in the Cévennes in south-eastern France and flows through Orléans, Tours, Angers and Nantes until it reaches the Bay of Biscay.
The Loire river is the longest river in France with 1013 km, and has a very large basin. The months of January to March are usually when the flow is at its highest point. Flowing and flood risk are increased by Cevenol rains (torrential downpours) in the southern part of the basin, and by the oceanic regime rains occuring in northwards zones, up from the Massif Central. In a rainy winter, the addition of both causes may cause a huge increase in the river flow (up to thousands of cubic metres/second). The creation of three dams on the upper part of the Loire river basin greatly reduced the risk of floods and allowed to support the frequently meager (a few tens of cubic meters/second) summer flow.
The Nile is navigable up to the first cataracts.
The merced river gets up to 50 ft wide at its widest point.
Sail up the Hudson River.
St.Lawrence river connects and drains the Great Lakes . It is the busiest inland waterway of the world It allows large ocean-going vessels from the Atlantic to reach the interior of America . The Mississippi River is navigable up to St.Louis and is also connected by canals to the Great Lakes. Thus opening up the interior of the vast American continent and establishing important river ports.
The point in a river where you encounter rapids. Seagoing ships can come up a river until they reach that point. Richmond VA is one city located at the fall line of the James River.
Source
Hopwell (originally City Point) was a deep water shipping point. At Richmond, you encounter the Fall Line- rocks in the river stopped ships from coming further up the river.
approx 25 miles
the rive nileIt's now under debate that the Amazon is the longest river in the world and is navigable for above and beyond 2000 miles, so perhaps the answer is not quite that simple... In 1874, an English captain by the name of Joseph Wiggins navigated his sailing vessel up the Yenisei River for 2,000 miles, although this is impossible today because of the dams built on it.
Egypt and any place in the delta.
The town grew up around the crossing point over the River Cam.