Before hitting land, Hurricane Harvey's status was upgraded to the second most destructive category for hurricanes -- a category 4 with winds of up to 130 miles per hour and 13-foot ocean surges.
The storm passed about 30 miles from Corpus Christi, a city of 320,000, and knocked out power to some homes in that city and nearby towns.
The National Hurricane Center said the storm could bring life-threatening floods in and around the city of Houston, the fourth biggest city in the United States. In all, nearly 6 million people lay in the storm's path.
Businesses have shut and residents have streamed out of coastal Texas as officials called for residents to evacuate ahead of Hurricane Harvey.
Oil companies have been evacuating staff from offshore platforms in the Gulf of Mexico.
Texan oil refineries on land have also closed their operations in preparation for the storm.
The halt to operations has seen U.S. fuel prices surge to a three-week high.
Based on reporting by Reuters and AP