Lennon, Smith, Souleret Engineering, Inc. (LSSE) founded in 1985 is a 75 person civil engineering and surveying firm with offices in Coraopolis (Allegheny County) and Greensburg (Westmoreland County), Pennsylvania. 

LSSE provides surveying, permitting, facilities planning, civil design and construction phase services, as well as grants/funding procurement and administration services for wastewater collection, conveyance and treatment; water supply/treatment/storage/distribution; roadway and pavement improvements; parks and recreational facilities; stormwater and flood control; general municipal infrastructure improvements; feasibility studies; master plans; and hydraulic and hydrologic modeling. Water and wastewater facilities projects range from small maintenance programs to capital improvement projects over $70 million in construction value.