It was approximately 55miles west-southwest offshore from Cihuatlan, in Jalisco state.
The USGS estimated the depth of the tremor at 10km.
It struck at 4.55am (BST).
Luis Felipe Puente, head of Mexico’s Civil Protection agency said on Twitter there were currently no reports of damage.
He added that the earthquake had been only lightly felt.
The Civil Protection agency has confirmed monitoring of the situation will continue.
Seismic activity is common in Mexico due to the fact that it sits on top of the devastating Ring of Fire – a series of fragile fault lines that stretches from New Zealand, all around the east coast of Asia, over to Canada and the USA then all the way down to the southern tip of South America.
The Ring of Fire region is a chain of volcanoes and intense earthquake tremor zones along the rim of the Pacific Basin.
The vast majority of the world’s earthquakes take place in the Ring of Fire and the zone holds more than 450 volcanoes and 75 percent of the world’s active fiery mountains.
The Ring of Fire extends a 40,000km-long horseshoe stretch of the Pacific Ocean.
A pair of devastating earthquakes hit Mexico in September, 2017.
More than 300 people were killed in a powerful earthquake in Mexico on 19 September and a week prior to that when the nation was hit by an 8.1 mega quake.