"a swathe of" is a valid and usable expression in written English.
It is used to refer to a large, broad amount of something. For instance, you could say, "The beach was flanked by a swathe of palm trees."
But a swathe of Obama's electorate felt the same way.
The rebels seized a swathe of northern Mali last spring.
A railway line protecting a swathe of Madagascan forest.
Next week the commission will designate a swathe of Harlem.
In the past two years, Bosnia has benefited from a swathe of reforms.
Johnston Press is disposing of staff photographers in a swathe of newspapers across England, reports HoldTheFrontPage.
A swathe of wasteland follows and then, further along, comes the town proper.
But they lost a swathe of close Senate races: Colorado, Minnesota, Missouri, Georgia and New Hampshire.
The highest price on a swathe of hair alone came from the head of Elvis Presley.
That leaves a swathe of northern Syria it controls, known as the Euphrates Shield zone.
There's a swathe of applications all using Fire Eagle now: Firebot updates Twitter with your location.
