FX’s “American Horror Story” returned Wednesday with the franchise’s largest ever audience, surging about 40% above its opener a year ago.

According to Nielsen, “American Horror Story: Coven” averaged a 3.0 rating/9 share in adults 18-49 and 5.54 million viewers overall — gains vs. last year’s “Asylum” premiere of 39% in the demo and 44% in total viewers. In 18-49, it easily beat competing broadcast dramas “CSI,” “Nashville” and “Ironside.”

And among all broadcast programs on the night, only ABC’s “Modern Family” (3.8) fared better.

Counting two quickie repeats of its premiere (at 11:12 p.m. and then 1:25 a.m.), “Coven” collected 7.78 million total viewers.

FX said Wednesday’s telecast could emerge as the most-watched program in network history when Live+7 DVR data becomes available.

“AHS” premiered in October 2011 with a 1.6 rating in adults 18-49 and 3.18 million viewers overall, and then returned a year ago to a series-best 2.2 demo rating and 3.85 million total viewers. “Asylum,” closed with a 1.3 and 2.29 million in January of this year.

Jessica Lange, Kathy Bates and Angela Bassett are among the cast for this season of “American Horror Story.”