So far placement of legend using the loc argument is limited to the inside of the axis (e.g. right, center, upper left, etc). However, often the plotting area is cluttered with the data points, and it is desired to place the legend outside of the axis, as for example described in http://matplotlib.org/users/legend_guide.html#legend-location

It would be useful to have additional loc values for quick and intuitive placement of the legend outside of the axis:

plt.legend(loc='outside right center')