Měiguó zǒngtǒng de tuǒyuánxíng bàngōngshì hěn yǒumíng.
The US president's Oval Office is famous.
Tips
usage
椭圆 (tuǒyuán) is the geometric ellipse; 椭圆形 adds 形 ("shape") to mean "oval-shaped / oval form," easier to use with 是…的 patterns. In math you'll see 椭圆 alone; in everyday description 椭圆形 is more natural.
culture
白宫 (the White House) 椭圆形办公室 = Oval Office. The Chinese name calques the English directly.