The Baltimore County Police Department was established by the General Assembly of Maryland on April 11, 1874.

The number of officers in the Baltimore County Police Department was cut from 33 to 10 as officers and station houses were absorbed into the Baltimore City Police Department on the western and northern "precincts" adjacent to the City.

The heavily industrial and residential communities on the east such as Highlandtown and Canton voted against annexation in the referendum and stayed in the county until 1919, when another 40 square miles (100 km2) of suburban and rural Baltimore County was annexed, causing the B.C.o.P.D.

In 1902, the Maryland General Assembly passed an act aimed at ensuring that officers appointed to the Baltimore County police force would be qualified.

The act required every applicant to provide their full name and age, location of birth, and prior occupations in the last two years, among other details.

It also required four "reputable" citizens of the county to speak of the applicant's character and affirm that they would be "fit for service".

Its main purpose was to classify fingerprints and photographs which would serve as an aid in solving crime.

's Towson Station killed two prisoners being held in the lockup, despite efforts by officers to pull the bars out of the windows using a tow truck.

joined the CODIS database allowing it to share and access DNA information to identify suspects.

The Baltimore County Police Department has faced criticism, mainly due to its lack of diversity and the history of its officers fatally harming citizens.

Additionally, the department has also begun trials on a take home vehicle program for patrol officers to add an incentive commonly seen in surrounding agencies for retention benefits.

This addition is to further allow officers to maintain high visibility in areas prone to criminal activity.

The primary duty firearm is the Glock 17 chambered in 9mm issued with Ameriglo 3 dot night sights, and a TLR-7 weapon mounted light.

The Remington 870 shotgun is issued to every marked patrol car, except specialized units like K9, BPI, and the Traffic units/Crash Team to name a few.

Axon T7 Tasers, Less Lethal beanbag shotguns and AR-15 patrol rifles are issued to some specifically trained officers.