Autofill range query

I'd like to use the following code

Cells(1, Counter).AutoFill Destination:=Range("E1:E" & lastrow)

but I want the "E"s to be the value of "counter". How do I code this?

Thanks.

It's not clear what you're doing with the first cell before hand (ie if you need to use AutoFill) but

With Cells(1,Counter)
    .AutoFill .Resize(lastrow)
End With