# `legend.linewidth` rcParam and parameter

A new rcParam `legend.linewidth` has been added to control the line
width of the legend\'s box edges. When set to `None` (the default), it
inherits the value from `patch.linewidth`. This allows for independent
control of the legend frame line width without affecting other elements.

The [.Legend]{.title-ref} constructor also accepts a new *linewidth*
parameter to set the legend frame line width directly, overriding the
rcParam value.

::: {.plot include-source="true" alt="A line plot with a legend showing a thick border around the legend box."}
import matplotlib.pyplot as plt

fig, ax = plt.subplots() ax.plot(\[1, 2, 3\], label=\'data\')
ax.legend(linewidth=2.0) \# Thick legend box edge plt.show()
:::