Don't hate me for this long pasted post regarding trailer mirror regulations:
Trailer Mirrors (Click here for Canada)
United States
Alabama
Rearview mirrors required on both sides.
Alaska
Two mirrors are required on a towing vehicle: the left side mirror is required, and 1 mirror may be an interior mirror.
Arizona
Vehicles with trailers that obstruct driver’s rear view must be equipped with mirrors that reflect at least 200 feet of the roadway.
Arkansas
Every motor vehicle which is so constructed or loaded as to obstruct the Driver’s view to the rear thereof from the Driver’s position shall be equipped with a mirror located so as to reflect to the driver a view of the highway for a distance of at least 200 feet to the rear of the vehicle.
California
A motor vehicle towing a vehicle or trailer must be equipped with mirrors on both the left and right side which provide a view of at least 200 feet of the highway.
Colorado
Every motor vehicle shall be equipped with a mirror or mirrors so located as to reflect to the driver a free and unobstructed view of the highway for a distance of at least 200 feet.
Connecticut
Every motor vehicle used for towing a house trailer must be equipped with a mirror located so as to give the operator a clear reflected view of the highway directly to the rear on a line parallel to the side of the body of the vehicle.
Delaware
All motor vehicles shall be equipped with a mirror placed so that the driver may readily ascertain the presence of any vehicle traveling in the same direction and overtaking the Driver’s vehicle.
District of Columbia
Must see 200 feet to rear.
Florida
Every vehicle operated singly, or when towing any other vehicle, shall be equipped with a mirror so located as to reflect to the Driver’s view of the highway for a distance of at least 200 feet to the rear of the motor vehicle.
Georgia
Every motor vehicle which is so loaded as to obstruct the Driver’s view through the rear of the vehicle must be equipped with a mirror so located as to reflect to the driver a view of the highway for a distance of at least 200 feet to the rear of the vehicle.
Hawaii
N/A.
Idaho
Left- and right-side mirrors are required if a Driver’s view straight to the rear is obstructed.
Illinois
Mirrors must give a view of 200 feet to rear.
Indiana
A motor vehicle that is constructed or loaded in a manner that obstructs the Driver’s rear view must be equipped with a mirror located in place where it is able to reflect the Driver’s view of the highway for a distance of at least 200 feet.
Iowa
Any motor vehicle towing another vehicle in such manner as to obstruct the view in a rearview mirror located in the Driver’s compartment must be equipped with a side mirror located so that the view to the rear will not be obstructed. When the vehicle is not towing another vehicle, the side mirrors must be retracted or removed.
Kansas
Every motor vehicle shall be equipped with a mirror on the left side and an additional mirror mounted either inside the vehicle in the center or outside the vehicle on the right side.
Kentucky
Every motor vehicle which is so loaded as to obstruct the Driver’s view to the rear must be equipped with a mirror so located and adjusted as to reflect a view of the highway for a distance of at least 200 feet to the rear.
Louisiana
Every semitrailer or trailer manufactured after December 31, 1972, must be equipped with a mirror mounted on the left side of the vehicle and so located as to reflect to the driver a view of the highway for a distance of at least 200 feet to the rear of the vehicle.
Maine
A person may not operate a vehicle so constructed, equipped, loaded, or used that the driver is prevented from having a constantly free and unobstructed view of the way immediately to the rear, unless there is attached a mirror or reflector placed and adjusted to afford the driver a clear, reflected view of the highway to the rear of the vehicle for a distance of at least 200 feet.
Maryland
Where the view through the inside mirror is obstructed, 2 outside rearview mirrors are required.
Massachusetts
Every motor vehicle, including trailers, shall be equipped with at least 1 mirror so placed and adjusted as to afford the operator a clear, reflected view of the highway to the rear and left side of the vehicle.
Michigan
Required.
Minnesota
Every motor vehicle, which is connected with another vehicle so that it obstructs the driver’s rear view, must be equipped with a rearview mirror that enables the driver to see for a distance of at least 200 feet to the rear of the last vehicle being towed.
Mississippi
Every motor vehicle that is loaded and obstructs the driver’s view to the rear shall be equipped with a mirror located to reflect to the driver a view of the highway for a distance of at least 200 feet to the rear of such vehicle.
Missouri
All motor vehicles, which are so constructed or loaded that the operator cannot see the road behind such vehicle by looking back or around the side of such vehicle, shall be equipped with a mirror so adjusted as to reveal the road behind and be visible from the operator’s seat.
Montana
A motor vehicle must be equipped with a mirror that reflects to the driver a view of the highway for a distance of at least 200 feet to the rear of the motor vehicle.
Nebraska
No person shall drive a motor vehicle on a highway when the motor vehicle is so constructed or loaded as to prevent the driver from obtaining a view of the highway to the rear unless such vehicle is equipped with a right-side and a left-side outside mirror so located as to reflect to the driver a view of the highway for a distance of at least 200 feet to the rear.
Nevada
Every truck having a body that obscures a view of the road to the rear shall be equipped with a mirror carried in such a position that the driver of the truck shall be able to see traffic approaching from the rear.
All motor vehicles shall have a mirror so located so as to reflect to the driver a view of the highway for a distance of at least 200 feet to the rear of the vehicle.
New Hampshire
No person shall drive upon any road any motor vehicle so loaded that the driver is prevented from having a constantly free and unobstructed view of the road immediately in the rear, unless there is attached to the vehicle a mirror or reflector so placed and adjusted as to afford the driver a clear, reflected view of the road in the rear of the vehicle.
New Jersey
No person shall drive a vehicle that is so constructed, loaded, or covered that the driver does not have a clear view of the traffic following and at its sides, unless the vehicle is equipped with a device that will show the road to the rear and side.
New Mexico
Every vehicle must be equipped with a mirror so located as to reflect to the driver a view of the highway from a distance of at least 200 feet to the rear of the vehicle.
New York
Every motor vehicle, when driven or operated upon a public highway, shall be equipped with a mirror or other reflecting device so adjusted that the operator of such vehicle shall have a clear and full view of the road and condition of traffic behind the vehicle.
Every motor vehicle when driven or operated on a public highway, that has a model year after
1968, shall be equipped with a side mirror which shall be affixed to the left outside of such vehicle and which shall be adjustable.
North Carolina
Vehicles that have an obstructed view of the rear of the vehicle must place a mirror so that it can reflect the view of the highway to the rear of the vehicle.
North Dakota
Every vehicle, operated singly or when towing any other vehicle, must have a mirror located to reflect to the driver a view of the highway for a distance of at least 200 feet to the rear of the vehicle.
Ohio
A left rearview mirror is required.
Oklahoma
Every motor vehicle towing another vehicle must be equipped with a mirror so located as to reflect to the driver a view of the roadway for at least 200 feet to the rear.
Oregon
All vehicles must be equipped with mirrors such that the driver has a clear and unobstructed view of the rear at all times and under all conditions of load that will enable the driver to see an approaching vehicle from a distance of not less than 200 feet.
Pennsylvania
Mirrors may extend on each side a maximum of 6 inches beyond the width of the vehicle or load, whichever is greater.
Rhode Island
Every vehicle that is so loaded that it obstructs the driver’s view to the rear, must have a mirror located for the driver so that it reflects a view of the highway for a list 200 feet to the rear.
South Carolina
Every motor vehicle that is constructed or loaded so that the driver’s rear view is obstructed, the driver’s position must be equipped with a rearview mirror that reflects the driver’s view of the highway for at least 200 feet.
South Dakota
Every motor vehicle when towing another vehicle must be equipped with a mirror located so that the driver has a rear view for a distance of at least 200 feet to the rear of the vehicle.
Tennessee
Required if vision from inside mirror is obstructed.
Texas
A motor vehicle, including a motor vehicle used to tow another vehicle, must be equipped with a mirror located to reflect to the driver a view of the highway for a distance of at least 200 feet from the rear of the vehicle.
Utah
Every motor vehicle shall be equipped with a mirror mounted on the left side of the vehicle and so located as to reflect to the driver a view of the highway to the rear of the vehicle.
Every vehicle shall be equipped with a mirror mounted either inside the vehicle approximately in the center or outside the vehicle on the right side and so located as to reflect to the driver a view of the highway to the rear of the vehicle.
Vermont
Required.
Virginia
Mirrors are required to give view of not less than 200 feet to rear of the vehicle; 1 outside and 1 inside. If inside view is obstructed to rear, then 1 on each side of the vehicle on the outside is required.
Washington
Every motor vehicle must be equipped with mirrors mounted on the left and right side of the vehicle and so located to reflect to the driver a view of the highway for a distance of at least 200 feet to the rear of such vehicle.
West Virginia
When a motor vehicle is constructed or loaded in such a way as to obstruct the driver’s view to the rear, mirrors must be equipped on the vehicle to give a view on the rear of at least 200 feet.
Wisconsin
Any vehicle must be equipped with a mirror or mirrors sufficient to reflect to the operator a view of the roadway for a distance of 200 feet to the rear of the vehicle.
Wyoming
Two mirrors are required, 1 on the left-hand side and 1 on the center of the windshield or the right-hand side. If the mirror on the windshield is obstructed, a right-hand mirror is required. It must be positioned to reflect to the driver a view of the highway to the rear of the trailer.
Puerto Rico
Rearview mirrors are required on both sides.
Canada
Alberta
Two side view mirrors are required on a towing vehicle where the rearview is obstructed by a trailer.
British Columbia
Two mirrors required; if trailer obstructs view through inside mirror, then 2 outside mirrors required.
Manitoba
Interior and left exterior mirrors are required when towing loads wider than the towing vehicle. Buses, trucks, and truck tractors require a left and right exterior mirror.
New Brunswick
Must give unobstructed view 60 meters to rear.
Newfoundland and Labrador
The towing vehicle in every combination of motor vehicles must be equipped with 2 mirrors, 1 placed on each side of the motor vehicle to provide the driver with a clear view of the roadway to the rear of the combination of vehicles.
Northwest Territories
No person may operate a vehicle unless it has at least 2 mirrors attached to the vehicle each of which gives the operator a clear view at least 60 meters behind the vehicle.
Nova Scotia
If the rearview mirror in a vehicle is obstructed or interfered with by a trailer or semitrailer attached to the motor vehicle, a rearview mirror must be attached to each side of the motor vehicle and placed so that the driver has a clear rear view for 60 meters on each side.
Nunavut
No person may operate a vehicle unless it has at least 2 mirrors attached to the vehicle each of which gives the operator a clear view at least 60 meters behind the vehicle.
Ontario
Extended mirrors may not extend past 305mm from the side of the tow vehicle.
Prince Edward Island
Every motor vehicle, other than a farm tractor, must be equipped with a mirror located and adjusted to give the driver an unobstructed rear view for at least 60 meters to the rear of the vehicle.
The operator of a towing vehicle which has an exterior accessory rearview mirror which extends beyond the length of a fixed standard mirror, or more than 10 inches beyond the body of the towing vehicle, must remove or fix the exterior accessory rearview mirror so that it is 250 mm or less beyond the body of the towing vehicle when the equipment being towed is disconnected.
Quebec
Where the motor vehicle pulls a trailer, rear view mirrors must be attached so as to enable the driver to have a clear view to the back of the combination of vehicles: (1) 1 rear view mirror attached to the exterior of the motor vehicle on the left side if the existing rear view mirror cannot be used; and (2) another rear view mirror attached to the exterior of the motor vehicle on the right side if the existing interior or exterior rear view mirror on the right side cannot be used.
Saskatchewan
When towing a trailer or another vehicle, the driver of the towing vehicle must have a clear view to the rear of the trailer or the other vehicle. Left and right outside mirrors set to the widest point of the towed vehicle(s) are sufficient.
Yukon
Where the driver’s view of the roadway to the rear of the vehicle is obstructed or interfered with in any manner, a side rear vision mirror must be attached to each side of the motor vehicle and must be placed in such a position as to afford the driver a clear view of the roadway to the rear and to each side of the motor vehicle.
http://drivinglaws.aaa.com/laws/trailer-mirrors/