Cheap Bus tickets to Portsmouth, NH, US

What are the most popular routes to Portsmouth?

Boston - PortsmouthAverage price£15Average duration1h 15mDaily departures2
New York City - PortsmouthAverage price£41Average duration7h 20mDaily departures8
Portland - PortsmouthAverage price£16Average duration1h 5mDaily departures2
Springfield - PortsmouthAverage price£26Average duration5h 10mDaily departures2
Augusta - PortsmouthAverage price£23Average duration2h 55mDaily departures2