Skip to Main Content Site Map

Analyzing Maryland’s Adjusted Redistricting Data

Used for US congressional and state legislative redistricting

Full Report

The expanded report provides a detailed breakdown of the PL 94-171 data as released by the Census Bureau, compared to the reallocated, or adjusted data, provided by the state’s official redistricting body.

Specifically, this report details the differences in total population by census block, block group, tract, county, and state before and after reallocation. In states where comparisons are possible, these population differences are broken down by race and ethnicity.



Maryland uses adjusted (or modified) data for US congressional and state legislative redistricting

  • 6,177,224 total population in the original PL file
  • 6,175,403 total population in the adjusted PL file
  • -1,821 total population difference between the two

Even in states where where the total population is unchanged, the distribution of population within the state can be affected.

To give you a sense for how these population shifts affect Maryland’s redistricting, the average district sizes in Maryland are:

  • 43,797 people per state House district
  • 131,391 people per state Senate district
  • 771,925 people per Congressional district

The dataset used to create this report is the official redistricting dataset.

County Level Analysis

See the appendix for a detailed breakdown of county level population changes.

Maryland's Adjusted Data Population Changes by County with Facility Locations

Block Level Analysis

In general, the changes in block population are not uniform: most blocks are unaffected by modification, while a handful of blocks lose a large amount of population that goes to a larger number of blocks in smaller quantities.

  • 83,827 census blocks in Maryland
  • 74,143 census blocks have the same population following modification
  • 9,662 census blocks gained population following modification
  • 22 census blocks lost population following modification (Of the 22 census blocks that lost population following reallocation, 21 contained facilities according to our analysis conducted with PPI data.)
  • 0 census blocks have a negative population following modification.
Population Change Number of Blocks
Gained 100+ 0
Gained 51-100 0
Gained 11-50 10
Gained 6-10 160
Gained 1-5 9,492
No Change 74,143
Lost 1-5 1
Lost 6-10 0
Lost 11-50 2
Lost 51-100 0
Lost 100+ 19

Official Language

The official language for Maryland’s adjustment is:

The population count used after each decennial census for the purpose of creating the legislative districting plan for the General Assembly: (1) may not include individuals who: (i) were incarcerated in State or federal correctional facilities, as determined by the decennial census; and (ii) were not residents of the State before their incarceration; and (2) shall count individuals incarcerated in the State or federal correctional facilities, as determined by the decennial census, at their last known residence before incarceration if the individuals were residents of the State


County Population Change
Baltimore City 3,871
Baltimore 2,138
Prince Georges 1,571
Montgomery 649
Wicomico 639
Harford 541
Frederick 268
Cecil 238
Charles 219
Dorchester 189
St Marys 181
Worcester 147
Calvert 142
Caroline 121
Talbot 72
Kent 41
Garrett 40
Queen Annes -40
Carroll -251
Howard -513
Allegany -2,254
Somerset -2,813
Anne Arundel -2,829
Washington -4,188