There are two types of Minimum Off Route Altitudes (MORAs) –
one is called a route MORA and the other is the grid MORA.

MORA's give at least 1,000' altitude clearance above terrain, and 2,000' in mountainous (elevation 5,000'+) terrain.

Route MORAs provided an obstacle clearance within 10 nautical miles (18.5 km) on both sides of the airways and within a 10 nautical miles (18.5 km) radius

Radius

In classical geometry, a radius of a circle or sphere is any line segment from its center to its perimeter. By extension, the radius of a circle or sphere is the length of any such segment, which is half the diameter. If the object does not have an obvious center, the term may refer to its...

 around the ends of the airways.

Grid MORAs provide an obstacle clearance altitude

Altitude

Altitude or height is defined based on the context in which it is used . As a general definition, altitude is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The reference datum also often varies according to the context...

within a latitude and longitude grid block, usually of one degree by one degree. They are presented in feet (ft), omitting the last two figures. Example: 7,600 feet is given as 76.

Grid MORA values clear all terrain and obstructions by 1000 feet in areas where the highest elevations are 5000 feet MSL or lower. MORA values clear all terrain by 2000 feet in areas where the highest elevations are 5001 feet MSL or higher.