USA

Production started in 1850s but took off 100 years later. It is firmly rooted by Champagne. 

California

• Location – Carneros AVA, Russian River valley AVA, Anderson Valley AVA
• Climate – Warm Mediterranean, sparkling wine grapes grown in the coolest areas where sea breezes and fog lowers the temperature.
• Grapes – Chardonnay & Pinot Noir

Some Champagne houses have subsidiaries in California and make sparkling wines here, for example:

• Taittinger – Domaine Carneros
• Mumm – Mumm Napa
• Moët & Chandon – Chandon Sparkling

Washington

• Location – Columbia Valley AVA
• Climate – Warm continental. Almost dessert like in the rainshadow of the Cascade Mountains. The climate is extreme with very warm summers and very cold winters (-26C). Northerly so days are long and diurnal range is very large. 
• Grapes – Mostly Chardonnay with some Riesling and PN. 

Well known producers: Treveri and Domaine St Michele (see Seattle Met)

Oregon

• Location – Willamette Valley AVA
• Climate – Cool Maritime. Most vines are directly exposed to the airflow of the Pacific, this gives milder winters and cooler and wetter summers. Long diurnal range.
• Grapes – Chardonnay and PN with Muscat, PG, Riesling and Müller-Thurgau.

Well known producers:  Argyle and Soter (see Food & Wine)

Viticulture & vinification

• Harvest – Grape destined for sparkling wines often picked two weeks earlier than the rest to maintain acidity
• Vinification high quality – Traditional method
• Minimum aging – There is no minimum aging but many producers age at least 12 months and for premium even higher
• Vinification high volume – Tank and carbonation 

Styles

• Style – Most popular Brut, also used is BdB, BdN and Rosé
• Vintage on label – 95% from that year
• AVA on label – 85% from that AVA (depending on the AVA)