Dear Ms. Grigsby,
Thank you for posting your request on History Hub!
We suggest that you review the National Archives African American Research website, the FamilySearch research wiki on African American Resources for Mississippi as well as the document Federal Records that Help Identify Former Slaves and Slave Owners.
We searched the National Archives Catalog and located the Population Schedules for the 1870 Census in the Records of the Bureau of the Census (Record Group 29) that may include records of Albert Grigsby. For access to the non-digitized schedules, please contact the National Archives at Washington, DC - Textual Reference (RDT1) via email at firstname.lastname@example.org.
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.
The 1870 Federal Census was the first time that African Americans were included in the registry, so prior to that only freed individuals were listed in the census. Formerly enslaved persons sometimes took the last name of the plantation owner so if you find Albert Grigsby in the 1870 Census, look in the same Enumeration District (local area of the county) for a Grigsby land owning family of European descent.
You may wish to search Ancestry.com for the U.S. Census. There may be a fee for using Ancestry. Instead, some of the images from Ancestry are available for free on Family Search or at your local library. Many library systems subscribe to these sites, making them free for their patrons.
We hope this is helpful. Best of luck with your research!