We determine the product of the expansion rate and angular-diameter distance at redshift $z=2.3$ from the anisotropy of Lyman-$\alpha$ ($\mathrm{Ly}\alpha$) forest correlations measured by the Sloan Digital Sky Survey (SDSS). Our result is the most precise from large-scale structure at $z>1$. Using the flat $\mathrm{\Lambda }$ cold dark matter model we determine the matter density to be ${\mathrm{\Omega }}_m=0.36_{-0.04}^{+0.03}$ from $\mathrm{Ly}\alpha$ alone. This is a factor of 2 tighter than baryon acoustic oscillation results from the same data due to our use of a wide range of scales ($25<r<180h^{-1}\mathrm{Mpc}$). Using a nucleosynthesis prior, we measure the Hubble constant to be $H_0=63.2\pm 2.5\mathrm{km}/\mathrm{s}/\mathrm{Mpc}$. In combination with other SDSS tracers, we find $H_0=67.2\pm 0.9\mathrm{km}/\mathrm{s}/\mathrm{Mpc}$ and measure the dark energy equation-of-state parameter to be $w=-0.90\pm 0.12$. Our Letter opens a new avenue for constraining cosmology at high redshift.

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• Cosmological constant
• Cosmological parameters
• Dark energy
• Large scale structure of the Universe