Some insects/imposters commonly mistaken as mosquitoes in our area include: 

Midges

Midge
A midge is a small fly, often mistaken as a
mosquito.
 
Midges often live and breed around water
sources containing lots of vegetation. You may
find them in "swarms" in nearby areas.

 

Gnats

 Fungus Gnat

Photo credit: Johnny N. Dell, Bugwood.org.

A gnat is a small flying insect, often mistaken
as a mosquito. The fungus gnat (pictured
above) is a non-biting insect, no bigger than
a few grains of salt.

What differentiates gnats from mosquitoes
is the lack of proboscis, the mouth-parts a
mosquito uses.

 

Crane Flies

 Crane Fly
A crane fly is often known as a Mosquito
Eater, but this insect does not eat
mosquitoes. It is actually harmless to
people, as another non-biting flying insect.
 
They can be as big as a silver dollar, and
are often described as "The Biggest
Mosquito I've Ever Seen!"

 

No-See-Ums / Sand Flies

 No-See-Ums / Sand Flies

Photo credit: James Gathany, phil.cdc.gov/.

A sand fly, or no-see-um, is a biting insect
that is small and often undetected, unless
they are biting you.

These flying insects lay their eggs in muddy
clay, and usually hatch when the mud dries
and cracks. 

 

Leafhoppers

 Leafhoppers
A leafhopper is an insect often found in
a yard or garden. Adult leafhoppers are
capable of biting humans, but they are
actually plant feeders.
 
These insects can really do a number on a
garden or yard, so landscapers are likely not
their biggest fans.