The United States aimed to force the Dominicans to repay their large debts to European creditors, whose governments threatened military intervention.

On May 13, 1916,[1] Rear Admiral William B. Caperton forced the Dominican Republic's Secretary of War Desiderio Arias, who had seized power from President Juan Isidro Jimenes Pereyra, to leave Santo Domingo by threatening the city with naval bombardment.

Three major roads were built, largely for military purposes, connecting for the first time the capital with Santiago in the Cibao, Azua in the west, and San Pedro de Macorís in the east; the system of forced labor used by the Americans in Haiti was absent in the Dominican Republic.

[2] In early May 1916, a conflict erupted in Santo Domingo between 800 supporters of President Juan Isidro Jimenes and 500 followers of Desiderio Arias, the Minister of War and a caudillo.

"[3] On May 6, American forces from the USS Castine landed to offer protection to the Haitian Legation, a country under a similar military occupation by the United States.

[4] On May 13, Rear Adm. William B. Caperton issued a demand for Arias, who was holed up in Fort Ozama, to disband his army and surrender his weapons.

Colonel Joseph H. Pendleton's Marine units took the key port cities of Puerto Plata and Monte Cristi on June 1 and enforced a blockade.

The first major engagement occurred on June 27, at Las Trencheras, two ridges, which had been fortified by the Dominicans and long thought to be invulnerable, since a Spanish army had been defeated there in 1864.

Marines overpowered Dominicans with modern artillery, Colt heavy machine guns, small-unit maneuver, and individual training and marksmanship.

Three days after Arias left the country,[1] the rest of the occupation forces landed and took control of the country within two months,[1] and on November 29, the United States imposed martial law and established a military government under Captain (later Rear Admiral) Harry Shepard Knapp, Commander of the Cruiser Force aboard his flagship, USS Olympia (which still exists today in Philadelphia, Pennsylvania, United States).

[1][13] On the same day that the U.S. military government was declared, First Lieutenant Ernest C. Williams led an assault on the fort at San Francisco de Macorís, where Juan Perez, a local governor and supporter of Arias, along with his followers, stood their ground and refused to surrender their weapons.

[6] During the early hours of the following evening, Williams led a detachment of 12 marines in a surprise attack on the fort and stormed the gate, resulting in a brief battle.

[6] Marines claimed to have restored order throughout most of the republic, with the exception of the eastern region, but resistance to the occupation from Dominicans continued widespread in both, direct and indirect forms in every place.

[14] The U.S. occupation administration, however, measured its success through these standards: the country's budget was balanced, its debt was diminished, economic growth directed now toward the U.S.; infrastructure projects produced new roads that allowed the movement of military personnel across all the country's regions for the first time in history;[15] a professional military organization that took away the power from local elites and made soldiers more loyal to the national government, the Dominican Constabulary Guard, replaced the former partisan forces responsible for the civil war with groups under the control of U.S.

[17] Most Dominicans greatly resented the loss of their sovereignty to foreigners, few of whom spoke Spanish or displayed much real concern for the welfare of the republic.

A guerrilla movement, known as the gavilleros,[1] with leaders such as General Ramón Natera, enjoyed considerable support from the population in the eastern provinces of El Seibo and San Pedro de Macorís.

[22] Among protestors to the occupation was the Junta Patriótica de Damas, (Patriotic League of Ladies) a group of feminist writers, led by Floripez Mieses, Abigail Mejía, Luisa Ozema Pellerano, and Ercilia Pepín, created on March 15, 1920.

[1] In the presidential election of March 15, 1924, Horacio Vásquez Lajara, an American ally who cooperated with the United States government, handily defeated Peynado.