Law firms are looking for marketing opportunities and courts are bracing for logistical challenges as the moon's shadow prepares to cross the United States from coast to coast Aug. 21.

Firms hope to capitalize on the solar eclipse event, which hasn't occurred like this in the U.S. for 99 years. Courts in cities along the 70-mile-wide band where the moon will totally block the sun for a couple of minutes are expecting masses to descend on their cities.

The event will be the fourth total eclipse witnessed by Mark Manner, a corporate partner at Bass, Berry & Sims in Nashville, Tennessee—and the first that he hasn't had to travel to be able to witness. He plans to be in an airplane above any clouds that threaten ground-based observations, but he said terra firma is a perfectly good base for watching the celestial show, especially as the moon's shadow approaches.