The Watermelon War was a riot that occurred on the morning of April 15, 1856 in Panama City in what was then the province of Panama in the Republic of New Granada, modern day republic of Colombia, .Throughout the 19th century U.S. involvement in the isthmus of Panama increased as it became the most convenient area in Central America for quick transoceanic transit. U.S. expansion westward accelerated after the Mexican–American War and the California Gold Rush and the United States felt a growing need for faster access to the pacific during a time when the American mid-west and western regions were difficult to travel. This led to recurrent negotiations between the governments of the Republic of New Granada, of which Panama was a province, and the United States of America. The focus of these early negotiations was for rights and protections concerning the free passage of goods and people through the isthmus.