General Motors produces this week the 1 millionth 5-passenger cross/utility vehicle on its Theta Epsilon architecture, a quicksilver metallic ’13 GMC Terrain Denali.

GM struck gold with the Terrain and its Chevrolet Equinox platform mate when the auto maker launched them in the U.S. in 2009 as ’10 models. Sales have grown ever since.

The two CUVs combined for 210,498 deliveries in their first full-year on the market, and sales rose 31.3% to 276,453 units in 2011, according to WardsAuto data. Through September of this year, deliveries were up 14% to 237,688 from 208,486 in like-2011.

The Equinox ranks as the sixth best-selling truck so far in 2012.

The 2.4L direct-injection 4-cyl. engine powering the ’10 Equinox and Terrain won a Ward’s 10 Best Engines award.

The popularity of the Equinox and Terrain is a positive manufacturing story for GM. The auto maker shuttered several assembly plants as part of its 2009 bankruptcy and restructuring, but the two CUVs have kept GM’s Ingersoll, ON, Canada, assembly plant running at capacity since launching.

To meet sustained demand,GM last year started shipping unfinished Equinox bodies from Ingersoll to nearby Oshawa, ON, for final assembly.

Earlier this year, GM reopened its Spring Hill, TN, facility to produce the Equinox. The factory had been idle since the auto maker consolidated production of all its large CUVs at its Lansing Delta Twp., MI, assembly plant.

“Chevrolet and GMC are both stronger brands with these vehicles in their showrooms,” Alan Batey, vice president-sales, service and marketing at GM, says in a statement.

To keep the two CUVs fresh, GM added for the ’13 model year items such as forward-collision alert, voice-activated connectivity and a more capable, 301-hp 3.6L direct-injection V-6 engine. The Terrain also added a premium Denali trim level.