American Militia Cavalry during the War of 1812 were wealthier men that could afford to equip themselves. The cavalry from Kentucky and Illinois wore hunting shirts, most other states had a variety of uniforms, we know the uniforms of about half of these. Overall, most uniformed cavalry had tartelans, stovepipe shakos, or a horse hair crest similar to the American line dragoons. All of the head gear used by cavalry in Europe were probably used by militia cavalry units somewhere in the United States. Companies were typically 30 to 50 men, units larger than that were almost always combined from 2 to 6 volunteer companies often all with different uniforms.
The plates shown below were created by "The War of 1812 Uniform Blog", that are relevant to the the Battle of Bladensburg. I have also included some plates from Osprey and Renee Chartrand. At the end of this post I will list what numbers I would use for 1 man equals 15 for this battle.
Most of their uniforms are unknown. Maryland state rules were that cavalry were to have a fur covered tartelan, and a dark blue jacket with braiding. Though at North Point, the majority seemed to be wearing stovepipe type shakos (as were many of the Maryland militia infantry). Militia cavalry often came up with their own uniforms.
This is my conjecture based on the fact the the "1st Harford County Light Dragoons" had their standard captured at the battle.
7th Maryland Cavalry District; Harford County-Lt. Col. / Major Unknown
Unknown Type; Captain Smith's Troop
Unknown Type; Captain Jenkin's Troop
Unknown Type; Captain Lee's Troop
Unknown Type; Unknown if 4th Troop existed
*The 1st Harford County Light Dragoons definitely had their standard captured by the British at the Battle of Bladensburg, this leads me to believe that these were troops were present. Some sources specify that it was the 7th Harford County District that was present at the battle.
*Since the uniforms for the Maryland cavalry at Bladensburg are mostly unknown, I would use the uniforms that are known for Maryland from North Point combined with state regulations.
Alexandria Dragoons (seen above)
The Alexandria Dragoons are named in many sources, I think they were probably the only DC troop present. One source stated that they were being used as couriers and scouts so were not much of a force at the battle.
I would use the Perry American War of Independence 16th Light Dragoons
Maryland 1st, 2nd and 5th Districts; 240 to 300 men 4 Companies (18 models)
1st Harford County Light Dragoons, plus 3 unknown troops
*X 6 Perry Plastic British Light Dragoons (Maryland Light Dragoons Uniform with Tartelons)
*X 6 Perry Plastic British Light Dragoons (Maryland Light Dragoon Uniform with Stove Pipe type hat)
District of Columbia Cavalry; 40 to 50 men; 1 Companies (3 models)
*X 3 Perry 3rd Continental Dragoons AWI (DC Alexandria Dragoons Uniform)
*X 9 Brigade Games or Knuckleduster American Light Dragoons plus a command figure. (10 total)
Virginian Light Dragoons; 100 men;
*X 6 Perry 16th Light Dragoon American War of Independence Models
*It is unclear, but it's possibly the reserve cavalry may have been combined in the second line as well.
Here are 3 of the Sources;