We have investigated lateral uniformity of pseudomorphic In0.05Ga0.95As/Al0.3Ga0.7As quantum wells (QWs) with well widths L-w of 2.4 and 3.6 nm grown on a (411)A InxGa1-xAs ternary substrate by molecular beam epitaxy. The lateral variation of In content (x) is from 0.054 to 0.063 over an area of 4 mm(2) in this substrate. In spite of the lateral variation of x in the (411)A InGaAs substrate (x = 0.054-0.063), full widths at half maximum (FWHMs) of the photoluminescence peaks (12 K) from the (411)A QWs are almost independent of the excitation position (FWHM = 9.0-9.7 meV for L-w = 2.4nm and 6.9-7.3 meV for L-w = 3.6 nm). Moreover they are approximately 20% smaller than those (FWHM = 11.0-11.3 meV for L-w = 2.4 nm and 8.6-9.0 meV for L-w = 3.6nm) of the corresponding QWs grown on a (100) In(0.06)Ga(0.94)Ad ternary substrate