Zaigrayevsky District is an administrative and municipal district (raion), one of the twenty-one in the Republic of Buryatia, Russia. It is located in the center of the republic. The area of the district is 6,605 square kilometers (2,550 sq mi). Its administrative center is the urban locality (an urban-type settlement) of Zaigrayevo. As of the 2010 Census, the total population of the district was 49,975, with the population of Zaigrayevo accounting for 11.2% of that number.

The district was established on February 11, 1935.

Within the framework of administrative divisions, Zaigrayevsky District is one of the twenty-one in the Republic of Buryatia. It is divided into two urban-type settlements (administrative divisions with the administrative centers, correspondingly, in the urban-type settlements (inhabited localities) of Zaigrayevo and Onokhoy), ten selsoviets, and one somon, all of which comprise forty-three rural localities. As a municipal division, the district is incorporated as Zaigrayevsky Municipal District. Zaigrayevo Urban-Type Settlement is incorporated as an urban settlement within the municipal district. The other urban settlement (Onokhoy Urban Settlement) within the municipal district incorporates the urban-type settlement of Onokhoy with the selo of Todogto and two rural localities in Dabatuysky Somon (the selo of Stary Onokhoy and the ulus of Onokhoy-Shibir). The remaining rural localities in Dabatuysky Somon and the ten selsoviets are incorporated as seventeen rural settlements within the municipal district. The urban-type settlement of Zaigrayevo serves as the administrative center of both the administrative and municipal district.

Historical population

Year	Pop.	±%
1939	31,500	—
1959	51,400	+63.2%
1970	51,400	+0.0%
1979	52,500	+2.1%
1989	56,200	+7.0%
2002	50,437	−10.3%
2010	49,975	−0.9%
2021	50,726	+1.5%
Source: Census data

• Правительство Республики Бурятия. Постановление №431 от 18 ноября 2009 г. «О реестре административно-территориальных единиц и населённых пунктов Республики Бурятия», в ред. Постановления №573 от 13 ноября 2015 г. «О внесении изменений в Постановление Правительства Республики Бурятия от 18.11.2009 №431 "О реестре административно-территориальных единиц и населённых пунктов Республики Бурятия"». Вступил в силу 18 ноября 2009 г. Опубликован: "Бурятия", №216, Официальный вестник №120, 21 ноября 2009 г. (Government of the Republic of Buryatia. Resolution #431 of November 18, 2009 On the Registry of the Administrative-Territorial Units and the Inhabited Localities of the Republic of Buryatia, as amended by the Resolution #573 of November 13, 2015 On Amending Resolution #431 of November 18, 2009 of the Government of the Republic of Buryatia "On the Registry of the Administrative-Territorial Units and the Inhabited Localities of the Republic of Buryatia". Effective as of November 18, 2009.).
• Народный Хурал Республики Бурятия. Закон №985-III от 31 декабря 2004 г. «Об установлении границ, образовании и наделении статусом муниципальных образований в Республике Бурятия», в ред. Закона №1411-V от 14 октября 2015 г. «О внесении изменений в Закон Республики Бурятия "Об установлении границ, образовании и наделении статусом муниципальных образований в Республике Бурятия"». Вступил в силу со дня официального опубликования. Опубликован: "Бурятия", №1, Официальный вестник №1, 12 января 2005 г. (People's Khural of the Republic of Buryatia. Law #985-III of December 31, 2004 On Establishing the Borders, Creating, and Granting a Status to the Municipal Formations in the Republic of Buryatia, as amended by the Law #1411-V of October 14, 2015 On Amending the Law of the Republic of Buryatia "On Establishing the Borders, Creating, and Granting a Status to the Municipal Formations in the Republic of Buryatia". Effective as of the day of the official publication.).