MONTPELIER — The state is investing $5 million to improve cellphone service in 21 southern areas and is on track to provide access to high-speed Internet service everywhere by the end of next year, Gov. Peter Shumlin said Friday.

The Vermont Telecommunications Authority, whose missions include securing access to affordable broadband services for all homes and businesses in the state and making sure its telecommunications infrastructure is continuously upgraded, has approved the grant to VTel Wireless, an affiliate of Vermont Telephone based in Springfield.

The project will use 27 of the towers or other structures that are already planned for VTel’s significant broadband project and new small cell sites on utility poles that are along fiber-optic lines that VTel owns or is developing, said Christopher Campbell, executive director of the Vermont Telecommunications Authority.

“This project is an important step forward toward providing cellular access across the state,” Campbell said.

VTel Wireless will be starting its own retail cellular service, with roaming agreements with national carriers.

The investment for cellular equipment through VTel Wireless will fill in some of the most challenging gaps in the southern part of the state, Shumlin said.

Service, he said, will improve on:

Andover Road between Andover and Weston;

Route 7 in Pownal;

Route 9 in Marlboro and Wilmington;

Routes 100 and 100A in Plymouth;

Route 100 in Wardsboro;

Route 103 in Mount Holly; and

Route 133 from Pawlet to Middletown Springs.

The state also is on target to get broadband computer service to every home and business by the end of 2013, Shumlin said. Now, 95.6 percent of Vermont E911 addresses are connected, compared with 87 percent when the project was started. That leaves 4.2 percent still lacking service.

“Help is on the way, and we expect to have you connected by our deadline,” Shumlin said.

The only holdups could be an extraordinarily snowy winter or if communities challenge the placement of cell equipment, he said.

Speed of the connection, too, has improved. The average speed has increased from 5.5 megabits per second to 9, making Vermont one of the leading states in average connection speed, said Connect Vermont Chief Karen Marshall.