Place carrots in a large bowl and drizzle with oil. Add salt and chili powder. Toss carrots until well coated.
Add orange slices and gently toss being careful not to tear the oranges.
Place carrots and oranges in a single layer on a large sheet pan.
Drizzle juice from bowl over carrots.
Roast at 400 degrees for 30 minutes. Flip carrots and oranges over and continue cooking 30 minutes or until they've starting browning.
Remove from oven and serve warm.