I went outside onto my deck. A single light, very visible in the sky, travelled parallel to the horizon for no more than 4 seconds. It went very fast, though it was a good distance away. I've seen satellites before, but the are typically not very bright and travel at a slow speed. This object was travelling very fast. I checked the ISS webpage and its nowhere near here.I'm assuming this is explainable, but am still curious enough to report this sighting.Sunset today was at 16:55.