This　paper　studies　adaptive　least-squares　finite　element　methods　for　convection-dominated　diffusion-reaction　problems.　The　least-squares　methods　are　based　on　the　first-order　system　of　the　primal　and　dual　variables　with　various　ways　of　imposing　outflow　boundary　conditions.　The　coercivity　of　the　homogeneous　least-squares　functionals　are　established,　and　the　a　priori　error　estimates　of　the　least-squares　methods　are　obtained　in　a　norm　that　incorporates　the　streamline　derivative.　All　methods　have　the　same　convergence　rate　provided　that　meshes　in　the　layer　regions　are　fine　enough.　To　increase　computational　accuracy　and　reduce　computational　cost,　adaptive　least-squares　methods　are　implemented　and　numerical　results　are　presented　for　some　test　problems.