Under the presidency of Julio Argentino Roca, the boundary treaty with Chile was signed in 1881, dividing the main island of Tierra del Fuego. At the end of that year, the Italian-Argentine Southern Expedition was launched, commanded by Navy Lieutenant Colonel Luis Piedra Buena, in command of the corvette Cabo de Hornos. Its chief scientist, Giaccomo Bove, is credited with identifying Ushuaia as a suitable location for a penal institution. During this expedition, they made contact with an Anglican mission located on the shores of the Beagle Channel, in Argentine territory.
Upon their return, the expedition presented the information obtained to the government along with a recommendation to build a lighthouse in San Juan, on the eastern tip of the Isla de los Estados. The Argentine government began planning a new expedition to ensure Argentine sovereignty in the southern territories through the construction of lighthouses and subprefectures. Luis Piedra Buena commanded the new expedition but did not participate because he died during the preparations. Augusto Lasserre was appointed in his place.
The South Atlantic Expedition, commanded by Ensign Augusto Lasserre, set sail from Buenos Aires in March, arriving in the port of San Juan in April. Construction began immediately. The San Juan de Salvamento lighthouse, also known as the "Lighthouse at the End of the World," was commissioned on May 25, 1884, and the remaining construction, including the subprefecture and the military prison, were completed in the following months. Once the works were completed, Captain Villarino and his crew took command, and the Expedition departed for the Beagle Channel, where the Anglican mission was located. They arrived at the end of September and made contact with Thomas Bridges, who was in charge of the mission, which had been evangelizing and teaching English to the indigenous peoples of the area since 1863. Lasserre explained to Bridges what the Argentine government had ordered him to do, and Bridges accepted Argentine jurisdiction without hesitation, advising Lasserre on the location for the construction of the subprefecture. On October 12, 1884, the subprefecture was completed, and the religious and official documents were signed by the inauguration committee, thus establishing Argentine sovereignty and peace.