Welcome to History Hub
According to the following Wikipedia article the first US Puerto Rico Census
was done in 1899, stated in article, prior to that it was done by Spain, ( But I could not find any Spain census for Puerto Rico)
Dear Mr. Cruz,
Thank you for posting your request on History Hub!
Since Puerto Rico became a United States territory in 1898 after the Spanish-American War and has been included in every Federal Census since 1900, we searched the National Archives Catalog and located the Population Schedules for the 1900 Census, the Population Schedules for the 1910 Census, the Population Schedules for the 1920 Census, the Population Schedules for the 1930 Census, , the Social and Population Schedules of the 1935 Special Census of Puerto Rico, 1935 - 1936, and the Population Schedules for the 1940 Census in the Records of the Bureau of the Census (Record Group 29) that may contain information about your great-grandfather’s family in Puerto Rico. The 1940 Census schedules are digitized and available using the Catalog. See NARA’s 1940 Census Records web page for more information. For access to the non-digitized schedules, please contact the National Archives at Washington, DC - Textual Reference (RDT1) via email at email@example.com.
Due to the COVID-19 pandemic and pursuant to guidance received from the Office of Management and Budget (OMB), NARA has adjusted its normal operations to balance the need of completing its mission-critical work while also adhering to the recommended social distancing for the safety of NARA staff. As a result of this re-prioritization of activities, you may experience a delay in receiving an initial acknowledgement as well as a substantive response to your reference request from RDT1. We apologize for this inconvenience and appreciate your understanding and patience.
For information about the U.S. Census, see the Census Bureau technical documentation and questionnaires.
You may wish to search Ancestry.com and FamilySearch.org for the U.S. Census and the 1935 Puerto Rico Territorial Census. There may be a fee for using Ancestry. Instead, check for access at your local library as many library systems subscribe to these sites, making them free for their patrons.
The Spanish Colonial census records of Puerto Rico are available at Censo Decenal 2010
For any civil records prior to 1898, including birth, marriage, and death records for your great-grandfather’s family, we suggest that you search the FamilySearch indexes for Puerto Rico, Civil Registration, 1805-2001 and Puerto Rico, Catholic Church Records, 1645-1969 as well as review the FamilySearch Research wiki for Puerto Rico Genealogy. We also suggest that you contact the Portada del Archivo Histórico Nacional in Madrid for information about their holdings of colonial Puerto Rican records.
We hope this is helpful. Best of luck with your family research!