[en] Knowledge of the ¹⁷F(p,γ)¹⁸Ne reaction rate is important for understanding stellar explosions, but it was uncertain because the properties of an expected but previously unobserved 3⁺ state in ¹⁸Ne were not known. This state would provide a strong s-wave resonance for the ¹⁷F+p system and, depending on its excitation energy, could dominate the stellar reaction rate at temperatures above 0.2 GK. We have observed this missing 3⁺ state by measuring the ¹H(¹⁷F,p)¹⁷F excitation function with a radioactive ¹⁷F beam at the ORNL Holifield Radioactive Ion Beam Facility (HRIBF). We find that the state lies at a center-of-mass energy of E_r=599.8±1.5_stat±2.0_sys keV (E_x=4523.7±2.9keV) and has a width of Γ=18±2_stat±1_syskeV. The measured properties of the resonance are only consistent with a J^π=3⁺ assignment