The bear has visited Broomall, Radnor Township and Haverford Township.
Keith Moyer says he came in close contact with the bear Sunday morning in Collingdale near Bartram Avenue.
Police agencies across the region have been trying to get the word out on social media, reminding people to keep their trash secured and keep a safe distance.
Officials say the bear has been spotted in neighborhoods around creeks and low lying areas.
Officials with the Pennsylvania Game Commission said it is uncommon for a bear to be seen in this area, but it's not unheard of.
This is the second or third sighting this year, they said, also mentioning they want people to call them immediately if they see the bear since it's so fast-moving. They also said they want to capture and relocate the bear without harming it, if possible.
Delaware County Emergency Services said there could be two bears on the loose because of how much ground has been covered over four days, as there have been sightings in at least seven communities from Radnor to Aston.
Authorities have been using drones to search for the bear.
"It's definitely the first time I saw a bear in Delaware County, I've lived here my whole life," said Lee Cowley.