As of 11 a.m local time (3 p.m. GMT), more than 205,000 customers in South Carolina were experiencing outages, while another 10,400 people faced blackouts in North Carolina, the website said.
Almost 7,000 customers were experiencing outages in the US state of Georgia, while another 4,000 people in Virginia had no electricity.
As of 10 a.m. local time, more than 73,000 customers in South Carolina were experiencing experience outages, while another 12,000 people in Georgia were experiencing blackouts, the website said.
Another 5,2000 customers face power cuts in the state of North Carolina, according to the outage tracker.
"Eyewall of Dorian just offshore of the eastern coast of South Carolina", the latest bulletin from the National Hurricane Center said about the location of the hurricane at 11:00 a.m. EDT (3:00 p.m. GMT). "On the forecast track, the center of Dorian will continue to move close to the coast of South Carolina today, and then move near or over the coast of North Carolina tonight and Friday".
Dorian is expected to make landfall in South Carolina or North Carolina on Thursday evening.
The National Hurricane Center earlier in the day warned that the approaching hurricane would likely cause life-threatening floods and tornadoes in both states.
On 1 September, Hurricane Dorian reached the highest-level Category 5 storm, damaging or destroying at least 13,000 housing structures on the Caribbean archipelago and killing at least five people.