The 1890 Census report on Vital and Social Statistics specifically covered cities with over 100,000 inhabitants. In Detroit:

“The area of the city on June 1, 1890 was 13,173 acres, and the number of dwellings was 86,993, containing 42,200 families and a total population of 205,870, giving an average of 2.81 dwellings and 15.63 persons to an acre, 5.57 persons to a dwelling and 4.88 persons to a family.

The colored population of the city was 3,454, located principally in wards 1, 3, 5, and 7. In the remaining wards the population of this class was too small to give rates of any value.”

Each ward has a table breaking down death rates for different races as well as children under age 5. Even without the tables it is visually apparent there were racial health disparities in Detroit with the highest death rates in the same wards as the largest number of Black residents.