That wasn't the only one, but it was the most "successful" from a Confed POV.
Elsewhere, circumstances on the ground were more amenable to guerrilla warfare. For example, the Kingdom of Jones (County) in Alabama, the Appalachians in Eastern Tennessee/Western North Carolina, and most spectacularly in NW Virginia, which successfully seceeded from Virginia's own secession

to create today's West Virginia!
Lesser known was the circumstances faced by the (New)-Mexicans at Sante Fe in the face of the CSA's invasion launched from El Paso. I shudder to think of what the Southrons would have wrought upon the Roman Catholic brown-skinned "Greasers"

that they had just curb-stomped a dozen years previously. But Canby, the Union commander, was unusually talented for a Northerner so early in the war, and he was the Union's undisputed master of desert warfare.
The Southern Rebels themselves were astonished at the level of ferocious resistance shown by the locals. "They never fought us this hard the last time...!" was a common Southern refrain in the Arizona Campaign

Not surprising, considering what the consequences would have been for the ethnic Mexicans and their families after a Southern victory. And I'm pretty sure this campaign was well after the Nueces Massacre. The German-Americans at Neuces were White, the Mexicans...were not. So just imagine.
Not that there weren't plenty of non-ethnic Anglo-American Unionists at Sante Fe, but the ethnic Mexican-Americans sure helped.
On top of all this, the Sante Fe garrison was blessed to have as their commander Colonel Edward R.S. Canby, the North's undisputed master of desert warfare. When the rebel army was defeated, he saw to it that the rebels were cut off from all water sources all the way back to El Paso. So of all the rebs who marched off from El Paso, few came back.