US Census data, recently updated, compares the levels of local government across America – Maryland is, as always, more consolidated than most states.
The Census recently updated 2017 data on local governance across the country. Its latest report is available online:
Individual State Descriptions: 2017 Census of Governments
the Maryland data begins on page 136 of the full report. From their Maryland summary:
For complete information from 2017 and earlier, visit the USE Census Bureau website on Government Organization and Structure.