Donald Duck medals that Dale Nelson earned from running in the Walt Disney World Half-Marathon hang in his home in Orlando, Fla. Dale and his wife, Betsy, left their law enforcement jobs in Ft. Lauderdale to move closer to Walt Disney World.

AP Photo/Phelan M. Ebenhack

Often called a half marathon, a mini-marathon is a tremendous test of endurance and running skill. At half the length of a full, 26.2-mile (42.16-kilometer) marathon, a mini-marathons' 13.1-mile (21.08-kilometer) course provides a challenge without the grueling length. While marathons usually get a lot of attention, dozens of mini-marathons also take place each year in the United States.

Make no mistake: Mini-marathons are not casual, non-competitive races. Like full marathons, the shorter mini-marathons keep times, maintain age divisions and often award prizes. Most likely, someone who is physically fit -- but not an athlete -- could finish a 5K or even a 10K without keeling over. (Those are 3.1 and 6.2-mile courses, respectively). However, running 13.1 miles is not easy. A mini-marathon is a physical test for regular, disciplined runners. Even if you run hard four to five days a week and train specifically for the big day, you should take the mini-marathon seriously.

Whether you've trained for the race or not, attending a mini-marathon is itself a lot of fun. Mini-marathons often occur along with another event, such as a full marathon, sporting event, parade or civic festival. Many mini-marathon sponsors place their focus on both having fun and giving to charity. Registration fees may benefit charities, some of which have been around for so long that they are events unto themselves. Charities may have their own fans, adherents and singular traditions.

Whether running a mini-marathon for charity, to prepare for a full marathon or to reach a personal goal, you'll know your months of training paid off when you finish the race. You'll become part of the nearly 1 percent of people worldwide who finish mini-marathons. So, go ahead and lace up your running shoes. Race day is around the corner.

Before you hit the pavement, though, let's look at some of the United States' biggest and best mini-marathons.