Is it really bad for a well maintained car to do this?

When i'm on the freeway, the speed limit is 70 mph but there are steep hills and i drive a honda fit i find myself at 4-5 k rpms at 70mph for 5 mins at a time is this bad

That's being pretty hard on it. It's a good way to overheat the engine and transmission and such wear and tear will reduce its useful life over time. Go slower on steeper hills, especially if you are heavily loaded or it is hot outside.

Your Honda Fit engine reaches peak peak horsepower @6600 RPM. The car has an ignition cut-off that won't allow the engine to run fast enough to do damage. As long as you follow the manufacturer's recommendations for service and maintenance, you should be good.

That's 4 to 5 thousand rpm's jojo… Does that make you feel any better?

The Fit is only 1600cc. To climb steep hills at 70 MPH, it will have to down shift a gear or two, Also if the vehicle has to down shift to climb a steep hill, and the A/C is on, shut off the A/C.

When I lived in LA and when you leave the city there are long uphill grades on the 5 and 15. They have specific signs there telling people to shut off their A/C going up those hills. Because on hot days there are cars all over the place along the sides of the road on the grapevine and the Tejon with blown cooling systems.

Otherwise, if you are concerned with the car, slow down a bit. Move to the right lane and keep it at 55 on these steep hills. The Fit is a city runabout and it is very good at that job. But it is not a long haul car meant to climb long uphill grades

Hi so why is it bad a modern Honda engine when under 8 years old and 100k miles should cope with 6000 rpm for at least 30 minutes with no bother.

Something could be misadjusted on the engine.