A fence system including a fence post and a rail inserted into and supported by the fence post. The rail being an elongated member having a channel or U-shaped cross section defined by a web member and parallel leg members attached to the web member. The rail is inserted into an aperture located in a sidewall of the post. The aperture having a shape or configuration that is substantially the same as the cross-sectional shape of the rail. Accordingly, any gaps between the opening or aperture in the post and the rail, once the rail is inserted into the post, are minimized.