Disc shaped object, approximatly 100 ft in air. large light and a strob in center. around 20-30 ft deep.

On or around 1975 mid summer while driving home from work about 11.30pm on Hwy 395 north of Spokane WA. from about 14 miles I saw directly ahead of me about 2 miles a bright light.  It looked like a football stadium at night from a distance.  Only in the air. I continued on,looking at the lights all the way.  As I got closer the lights were larger and very close to the ground. I had one more hill to go up before I reached my turn, Just about 1/2 milefrome the town of Deer Park. I climbed the hill watching the lights all the way.  As I reached the crest of the hill I was directly in front of the object.  It covered the highway on one side, the center  of the object was off the road to the left directly over a small farm house the barn and sourounding property.  As I look back I would say it was roughly 3-4 hundred yards round 30-40 ft high. with large lights all the way around and a large strob like light in the center (no colored lights) which was in the center on the bottom.  The object was only obout 100ft off the ground.  I do not recall any noise. As I drove directly under the object I had to make my turn (right). So I drove under and looked up, I do not recall seeing anthing other than lights and the strob.  I made my turn and stoped.  I got straight out to get a better look and it was just gone.  The only thing in the clear sky was stars...  Not a sign of what I had been watching nothing what so ever... I had no missing time, or any reason to think anything wierd had occurd..  Just a lasting memory.