January – February – March – April – May – June – July – August – September – October – November – December
- January 1, 1775 - The Municipality of Caguas was founded.
- January 2, 1949 - Luis Muñoz Marín becomes the first democratically elected Governor of Puerto Rico
- January 2, 1965 - Roberto Sánchez Vilella becomes Governor of Puerto Rico
- January 2, 1969 - Luis A. Ferré becomes the first pro-statehood Governor of Puerto Rico
- January 2, 1973 - Rafael Hernández Colón begins the first of three non-consecutive terms as Governor of Puerto Rico
- January 2, 1977 - Carlos Romero Barceló becomes Governor of Puerto Rico
- January 2, 1977 - Carlos S. Quirós begins a days-long term as Mayor of San Juan
- January 2, 1993 - Pedro Rosselló becomes Governor of Puerto Rico
- January 2, 2001 - Sila Calderón becomes the first female Governor of Puerto Rico
- January 2, 2005 - Aníbal Acevedo Vilá becomes Governor of Puerto Rico
- January 2, 2009 - Luis Fortuño becomes Governor of Puerto Rico
- January 2, 2006 - Death of Raúl Dávila, actor, All My Children (b. 1931)
- January 9, 1963 - Death of Ernesto Ramos Antonini, co-founder of the Partido Popular Democrático de Puerto Rico (Popular Democratic Party of Puerto Rico) (b. 1898)
- January 10, 1967 - Birth of Trini Alvarado, actress
- January 10, 1973 - Birth of Félix 'Tito' Trinidad, middleweight boxing champion
- January 11, 1839 - Birth of Eugenio María de Hostos, educator and independence advocate (d. 1903)
- January 12, 1956 - Birth of Roberto Vigoreaux, television producer, actor, and politician
- January 12, 1987 - Birth of Naya Rivera, actress (most notably GLEE)
- January 15, 2009 - Death of Tommy Muñiz, comedian, dramatic actor, network owner and producer
- January 17, 1983 - Death of Luis Vigoreaux, radio and television show host, announcer, comedian and producer (b. 1929)
- January 19, 1957 - Birth of Kenneth McClintock, Secretary of State and former President of the Senate of Puerto Rico, London, England
- January 19, 1958 - Birth of José Aponte, former Speaker of the House of Representatives of Puerto Rico, San Lorenzo, Puerto Rico
- January 19, 1974 - Death of Antonio Fernós-Isern, the first Puerto Rican cardiologist and the longest serving Resident Commissioner (b. 1895)
- January 19, 1985 - Death of Juan Antonio Corretjer, poet, journalist and independence political activist (b. 1908)
- January 21, 1895 - Birth of Concha Meléndez, educator, poet, and writer (d. 1983)
- January 22, 2002 - Death of Manuel Méndez Ballester, journalist, radio and television broadcaster, and teacher (b. 1909)
- January 24, 1880 - Death of José Gautier Benítez, considered Puerto Rico's best poet of the Romantic Era (b. 1848)
- January 27, 1975 - Birth of Iván Calderón, professional boxer
- January 28, 2004 - Death of José Miguel Agrelot, Puerto Rican comedian, radio and television host and media icon known for his Don Cholito character (b. 1927)
- January 29, 1736 - The Municipality of Guayama was founded.