Based on psoft‘s excellent information, I was able to achieve what I was looking for with this code.
NSString *location = @"some address, state, and zip";
CLGeocoder *geocoder = [[CLGeocoder alloc] init];
[geocoder geocodeAddressString:location
completionHandler:^(NSArray* placemarks, NSError* error){
if (placemarks && placemarks.count > 0) {
CLPlacemark *topResult = [placemarks objectAtIndex:0];
MKPlacemark *placemark = [[MKPlacemark alloc] initWithPlacemark:topResult];
MKCoordinateRegion region = self.mapView.region;
region.center = placemark.region.center;
region.span.longitudeDelta /= 8.0;
region.span.latitudeDelta /= 8.0;
[self.mapView setRegion:region animated:YES];
[self.mapView addAnnotation:placemark];
}
}
];