A tree that fell onto a utility pole at Holt Road and Clark Street in North Andover, off Route 125, was the cause of a power outage that began at noon Thursday and affected about 8,000 National Grid customers.
The customers were in parts of North Andover, South Lawrence and Haverhill.
Power was restored to most of those customers by 1:30 p.m., said National Grid spokesman Bob Kievra.
According to a National Grid map, the outage affected the North Andover areas of North Andover High School, Lake Cochichewick, Lawrence Municipal Airport, Den Rock Park, Shawsheen Village and Merrimack College, as well as several smaller pockets in the town, and sections of South Lawrence near Lawrence High School and Colonial Heights.
Power was also out to a few homes in the Bradford section of Haverhill near the North Andover line, but was quickly restored, Kievra said.
Kievra said the tree knocked down a utility pole carrying a high capacity power line that feeds electrical substations.
"We replaced the pole and were able to isolate the outage and reroute power elsewhere," he said.