Control C# checkbox using variable

I have this code:

// code above
 checkBox1.Checked = false;
 checkBox2.Checked = false;
 checkBox3.Checked = false;
 checkBox4.Checked = false;
 checkBox5.Checked = false;
 checkBox6.Checked = false;
 checkBox7.Checked = false;
 checkBox8.Checked = false;
 checkBox9.Checked = false;
//code below

I have 320 checkBoxes to set cleared/false.

How do I control checkBox(variable)?

I would like to do the following:

for (int counter=1; counter<321; counter++)
{
 checkBox***Put counter Variable Here***.Checked = false;
}