We present “ On The Fly ” maps of the CO ( 1-0 ) and CO ( 2-1 ) emission covering a 10′ \times 10′ region of the NGC 6946 . Using our CO maps and archival VLA HI observations we create a total gas surface density map , \Sigma _ { gas } , for NGC 6946 . The predominantly molecular inner gas disk transitions smoothly into an atomic outer gas disk , with equivalent atomic and molecular gas surface densities at R = 3.5′ ( 6 kpc ) . We estimate that the total H _ { 2 } mass is 3 \times 10 ^ { 9 } M _ { \sun } , roughly 1/3 of the interstellar hydrogen gas mass , and about 2 % of the dynamical mass of the galaxy at our assumed distance of 6 Mpc . The value of the CO ( 2-1 ) /CO ( 1-0 ) line ratio ranges from 0.35 to 2 ; 50 % of the map is covered by very high ratio , > 1 , gas . The very high ratios are predominantly from interarm regions and appear to indicate the presence of wide-spread optically thin gas . Star formation tracers are better correlated with the total neutral gas disk than with the molecular gas by itself implying \mbox { $ \Sigma _ { SFR } $ } \propto \mbox { $ \Sigma _ { gas } $ } . Using the 100 \mu m and 21 cm continuum from NGC 6946 as star formation tracers , we arrive at a gas consumption timescale of 2.8 Gyr , which is relatively uniform across the disk . The high star formation rate at the nucleus appears to be due to a large accumulation of molecular gas rather than a large increase in the star formation efficiency . The mid-plane gas pressure in the outer ( R > 10 kpc ) HI arms of NGC 6946 is close to the value at the radial limit ( 10 kpc ) of our observed CO disk . If the mid-plane gas pressure is a factor for the formation of molecular clouds , these outer HI gas arms should contain molecular gas which we do not see because they are beyond our detection limit .