It builds on the $1bn investment the group has spent on its US supply chain over the past five years, which added 1,000 jobs.
The company said its latest investment would ensure more than 95% of its products for the US are produced in the country.
Mars Chocolate North America president, Tracey Massey, said:“The $70m is across our existing factories for M&M’s. We are seeing really good growth for our core M&M’s products, so [we’re] expanding that to produce more.
“And also in Albany, Georgia, where last year we launched a product calls goodnessknows – [we’re] expanding there with new varieties, new flavors," she told CNBC.
Mars will add 250 jobs across its US production network under the move.
M&M’s and goodnessknows
The company launched portion-controlled snack bar brand goodnessknows in August 2015, which is produced at its Albany, Georgia, factory.
Nielsen expects the US better-for-you snack bar category will record a five-year compound annual growth rate (CAGR) of 5% to reach $6.8bn by 2019.
Mars added three goodnessknows flavors in December 2016: Blueberry & Almond, Mixed Berry & Almond and Strawberry & Peanut.
The company will also introduce M&M’s Caramel in May this year. The SKU – described by Massey as the company’s “biggest innovation ever” - will be produced in Topeka, Kansas, under a previously announced $100m production line investment with 70 added jobs.
Massey said confectionery was a “robust category” and said she expects future growth.
The US chocolate market grew retail value sales by 3.5% year-on-year in 2016 to reach $18.8bn, according to Euromonitor International. The global market grew 4.8% in retail value over the same period.
Euromonitor expects the US chocolate market will grow value sales by 9.9% from 2016 to 2021 – albeit at a slower rate the global market (+12.1%).