Set in California, The Squatter and the Don is a historical romance that explores America's 19th century territorial expansion into the Southwest and the repercussions this had on the native Californios. Centering on two families—the Alamars of the landed Mexican gentry, and the Darrells, the wealthy New England "squatters" who contest the Alamars' right to their land, Ruiz de Burton's most famous work is simultaneously a romance populated by appealing characters and also a blunt critique of America's policies and values. Following in the tradition of Romeo and Juliet, Clarence Darrell, the young, liberal, enterprising son of William Darrell, falls in love with Don Mariano's bright, lovely daughter, setting the state for a romance that is deeply concerned with issues of race, privilege, and justice. Ruiz de Burton also focuses on the effects of the swift, powerful rise of corporate monopolies—such as the railroad trusts—their shocking influence in Washington, and their lack of concern for ordinary citizens deeply affected by their actions.