A detailed analysis of ground-based CCD UBV photometry and space-based Gaia Data Release 3 (DR3) data for the open clusters King-6 and NGC-1605 was performed. Using the pyUPMASK algorithm on Gaia astrometric data to estimate cluster membership probabilities, we have identified 112 stars in King 6 and 160 stars in NGC-1605 as the statistically most likely members of each cluster. We calculated reddening and metallicity separately using UBV two-color diagrams to estimate parameter values via independent methods. The color excess E(B-V) and photometric metallicity [Fe/H] for King-6 are 0.515{+/-}0.030mag and 0.02{+/-}0.20dex, respectively. For NGC-1605, they are 0.840{+/-}0.054mag and 0.01{+/-}0.20dex, respectively. With reddening and metallicity kept constant, we have estimated the distances and cluster ages by fitting PARSEC isochrones to color-magnitude diagrams based on the Gaia and UBV data. The photometric distances are 723{+/-}34pc for King-6 and 3054{+/-}243pc for NGC-1605. The cluster ages are 200{+/-}20Myr and 400{+/-}50 Myr for King-6 and NGC-1605, respectively. The mass function slopes were found to be 1.29{+/-}0.18 and 1.63{+/-}0.36 for King-6 and NGC-1605, respectively. These values are in good agreement with the value of Salpeter. The relaxation times were estimated as 5.8Myr for King-6 and60 Myr for NGC-1605. These indicate that both clusters are dynamically relaxed since these times are less than the estimated cluster ages. A Galactic orbit analysis shows that both clusters formed outside the solar circle and are members of the young thin-disk population.